This forest has now been ported to Forester 6.0. You may need to clear your cache to get rid of stale stylesheets or redirects. Despite the fact that the HTML backend of Forester 6.0 doesn't support any customisation, I was able to inject my customisations including Gregorian chants, syntax highlighting, TSV tables and most of my style tweaks simply by making a custom Forester 6.0 theme that replaces the existing style.css with a file that @imports my additional style sheets, and similarly the min.js with a file that imports all of my custom scripts.

There were a few bugs or minor things that I had to fix, that I'll document here:

• The new search dialog looks for forest.js in the wrong place, so I hardcoded a fix for my forest in my custom theme.
• The generated pages preload katex.min.css but don't actually load it. I put a @import(katex.min.css) line into my stylesheet to fix this.
• The generated index.html redirects to the wrong place, so I put a custom index.html in the custom theme that overrides Forester's generated one.
• The top-level .block elements in a page didn't have the data-taxon attribute which my custom stylesheet depends on. I guess this is also a bug, as it's a regression from the previous Forester 5.0 pages. I added this to the Forester source code in my private fork.
• The download link meta-data that I added custom to my XSLT sheet in Forester 5.0 is now hardcoded in my private fork of Forester 6.0. Perhaps when more customisation options are added (and the above bug fixed), I will not need a private fork anymore, as this is really the only customisation I had that cannot already be accommodated by my custom theme.

Mihi autem nimis honoráti sunt amíci tui, Deus: nimis confortátus est principátus eórum.
Ego clamávi, quóniam exaudísti me, Deus: inclína aurem tuam, et exáudi verba mea: custódi me, Dómine, ut pupíllam óculi: sub umbra alárum tuárum prótege me.

This morning at All Saints Ainslie we sang Be still for the presence of the Lord, which is way too 1980s for my taste but it is what it is:

Be still, for the presence of the Lord,

the Holy One is here.

Come, bow before Him now,

with reverence and fear.

In Him no sin is found,

we stand on holy ground.

Be still, for the presence of the Lord,

the Holy One is here.

Be still, for the glory of the Lord,

is shining all around.

He burns with holy fire,

with splendor He is crowned.

How awesome is the sight,

our radiant King of Light!

Be still, for the glory of the Lord,

is shining all around.

Be still, for the power of the Lord,

is moving in this place.

He comes to cleanse and heal,

to minister His grace.

No work too hard for Him,

in faith receive from Him.

Be still, for the power of the Lord,

is moving in this place.

We chose this anthem because our original plan was too ambitious, and we had sung this anthem the day before at the wedding of Sajay (one of our choristers) and Jaclyn, along with Bob Chilcott's Be thou my vision.

Si iniquitátes observáveris Dómine, Dómine quis sustinébit? quia apud te propítiatio est, Deus Israel.

This morning at All Saints Ainslie we had a very small choir so we sang some established repertoire with me as the only tenor and our director managing the soprano part, Byrd's Ave Verum Corpus:

Ave verum corpus natum de María Vírgine,	Hail, true body, born of the Virgin Mary,
Vere passum immolátum in cruce pro hómine,	True suffering, sacrificed on the cross for Man,
Cuius latus perforátum unda fluxit sánguine,	From whose pierced side flowed waves of blood,
Esto nobis prægustátum in mortis exámine.	Be for us a foretaste in death's trial.
O dulcis, O pie, O Iesu fili Maríæ,	O sweet! O blessed! O Jesus, son of Mary,
Miserére mei, miserére mei, miserére mei.	Have mercy on me, have mercy on me, have mercy on me.

OpenAI have foisted upon the mathematical community a dump of hundreds of new "results" in mathematics, excreted by their machines. I hope it goes without saying that this is a disgusting abuse of the mathematical community and the intellectual commons. I refer to the statement by the Association for Human Mathematics:

Releasing over 700 files at once is not a demonstration of scholarship, but a demonstration of power. We urge mathematicians to discontinue their work with OpenAI and to return to a vision of science that centers human understanding.

I also quote Antonio E. Porreca from his excellent reaction to this:

I believe that we, as researchers and teachers, must reject AI-powered “papers” like these as legitimate research, because they’re not. And even if they were, it’s research that’s not worth doing. It does not follow any of the rules or the values of academia: building on the work of others with citations, not scooping your colleagues, collaborating, learning, teaching… and, you know, actually writing your own stuff in good faith. We have a right not to read papers like these, we have a right, no, a duty, not to cite them, to refuse refereeing them.

Even if you, as a “senior” (meaning, with a permanent academic position) believe that it’s OK for yourself to do AI-powered “research”, you should think about your students and your junior and future colleagues. AI-powered “research” is not self-sustaining: you will always need a human expert in the loop, even if it’s just for asking question to your LLM chatbot, filtering all bullshit answers, and interpreting and applying the result (a job I wouldn’t wish on my worst enemy). If AI-powered “research”, let alone “teaching”, becomes the norm, we’ll lose at least a generation of human experts. I’ve personally witnessed whole classes of students pressured (by peers and, above all, by the behaviour of their teachers and the university bureaucrats) into using LLMs to write code. These students are not learning. They will never be the human expert in the loop. And the same thing will happen to our junior colleagues, if you force them to use LLMs to do their job. In fact, one day there will be no expert at all. Even if you don’t believe that, one day you will lose your expertise too if you let LLMs do your science for you. Snap out of it.

In voluntáte tua, Dómine, univérsa sunt pósita, et non est qui possit resístere voluntáti tuæ: tu enim fecísti ómnia, cælum et terram, et univérsa quæ cæli ámbitu continéntur: Dóminus universórum tu es.
Ego autem sicut olíva fructificávi in domo Dómini, sperávi in misericórdia Dei mei: et exspectábo nomen tuum, quóniam bonum est ante conspéctum sanctórum tuorum.

This morning I sang with a skeleton crew choir at All Saints Ainslie, for an, uh, interesting service replete with all the dogs of the congregation. The animal blessing itself was a bit too Common Worship for my taste, but it was nice to see all the cute animals. We sang Brother James' Air:

The Lord's my Shepherd, I'll not want.

He makes me down to lie

In pastures green; He leadeth me

The quiet waters by.

He leadeth me, He leadeth me,

the quiet waters by.

My soul He doth restore again;

And me to walk doth make

Within the paths of righteousness,

Ee'n for His own Name's sake.

Within the paths of righteousness,

Ee'n for His own Name's sake.

Yea, though I pass through shadows death,

Yet will I fear no ill;

For Thou art with me; and Thy rod

And staff me comfort still.

Thy rod and staff they comfort still

They comfort still.

My table Thou hast furnishd

In presence of my foes;

My head with oil thou dost anoint,

And my cup overflows.

My head thou dost with oil anoint,

And my cup overflows.

Goodness and mercy all my days

Will surely follow me;

And in my father's heart alway

My dwelling place shall be.

We (being Coro) performed to a sizeable but not sold-out crowd for our second concert of the year, Cloudburst.

I really enjoyed working with our guest director, Roland Peelman, and it was great to have the opportunity to sing Tallis' Lamentations of Jeremiah (Part 1 and Part 2).

The full programme is outlined in this review from Jacqui Smith at classikON.

What a treat to hear a new choir (for me) performing such a profound and deeply moving program, with excellent artistic programming, pace and delivery. I can’t wait to hear what they sing next.

There was also a more nitpicky review on CityNews.

I'll likely be singing again with a subset of Coro for a special Christmas concert. Stay tuned!

Benedícite Dóminum, omnes Angeli eius, poténtes virtúte, qui fácitis verbum eius, ad audiéndam vocem sermónum eius.
In nómine Dómini omne genu flectátur, cæléstium, terréstrium et infernórum: quia Dominus factus obédiens usque ad mortem, mortem autem crucis: ídeo Dóminus Iesus Christus in glória est Dei Patris.
Omnia quæ fecísti nobis, Dómine, in vero iudício fecísti, quia peccávimus tibi, et mandátis tuis non obedívimus: sed da glóriam nómini tuo, et fac nobíscum secúndum multitúdinem misericórdiæ tuæ.

This morning I was groggy after a night at the German club after my Cloudburst concert had wrapped up, but still cantored at All Saints Ainslie in a duet with our director Alasdair, singing Dering's Duo Seraphin:

Duo séraphim clamábant alter ad álterum:	Two seraphs cry out one after another:
Sanctus, Sanctus, Sanctus Dóminus, Deus Sabaoth	Holy, Holy, Holy Lord, God of Hosts
Plena est omnis terra glória eius.	All the earth is full of his glory.

We also came together in the evening with the rest of the choir to sing Evensong. I think we sang exceptionally well but only seven or so people came to hear it. We sang Stainer's Hail, Gladdening Light as usual, as well as Phillip Moore's third service for the Magnificat and Nunc Dimittis. For the preces and responses, we used Jack Oades' lovely setting. The anthem was John Goss' O Saviour of the World:

O Saviour of the world,

who by thy Cross and precious Blood

hast redeemed us:

Save us, and help us,

we humbly beseech thee, O Lord.

Amen.

I'm still annoyed by the anticipation of the feast day, but I'll never get my way here.

Today we had our regular PhD monitoring event, where all students and faculty in the Foundations cluster go to a remote location for a day, listen to some talks, and hold interviews with students where we ensure they're well supported. We went, as with last time, to the Cuppacumbalong Homestead for this event.

This time the schedule felt quite relaxed and I had a nice time, although I was still suffering from jetlag. My student Kai Phan said she had a better time this time around, which makes me glad.

Salus pópuli ego sum, dicit Dóminus: de quacúmque tribulatióne clamáverint ad me, exáudiam eos: et ero illórum Dóminus in perpétuum.
Eúntes, docéte omnes gentes, baptizántes eos, et docéntes eos serváre ómnia quæcúmque mandávi vobis, dicit Dóminus.

Today I returned to my usual All Saints Ainslie in the morning where we sang Mozart's Ave Verum Corpus under my (metaphorical) baton:

Ave verum corpus natum de María Vírgine;	Hail, true body, born of the Virgin Mary;
Vere passum, immolátum in cruce pro hómine;	True suffering, sacrificed on the cross for Man;
Cuius latus perforátum unda fluxit et sánguine	From whose pierced side flowed waves of blood,
Esto nobis prægustátum in mortis examine.	Be for us a foretaste in death's trial.

I'm still annoyed by the anticipation of the feast day, but I don't think the rector is movable on this subject.

We had a celebration of Gordon Plotkin's eightieth birthday today, featuring many interesting talks. It's hard not to run into Gordon's work if you do anything involving semantics or concurrency or programming languages. My favourite talk of the day was probably my friend Ningning Xie's talk, but I also enjoyed Rob van Glabbeek's talk on his Justness work.

My only major Gordon anecdote is that he was on my interview panel when I interviewed for the job at the University of Edinburgh, and I was astounded to realise that not only was he still alive, but also he somehow didn't appear much older than any of the famous pictures of him.

So, congratulations and happy birthday to the timeless Gordon Plotkin, a huge contributor to our field and an intellectual hero to many of us.

We had a celebration of 40 years since the foundation of the Laboratory for Foundations of Computer Science (LFCS) by Robin Milner, Rod Burstall and Gordon Plotkin today. This was the institute that I was (and in some sense, remain) part of at the University of Edinburgh. I don't have much time for navel-gazing, and sadly most of the technical talks were either well outside my area, a demonstration of how brain-poisoned by LLMs my former Edinburgh colleagues have become, or both. I didn't really get much out of the day.

I am still glad to be here in Edinburgh for this week, though. It's great to catch up with some old friends.

While his birthday was back in April, to fit with Plotkin 80 and LFCS 40, we had a birthday event for Philip Wadler today, celebrating his 70th year.

I really loved Conor's talk on dependent session types, which was inspired by a question from Phil ten years earlier at his 60th birthday event. Her proposed design resembles Peter Hancock's interaction structures quite a bit. Very nice work.

I also gave my talk, which I peppered with many anecdotes about meeting Phil. I got a lot of interest about potentially using Holbert-ng, including from Marcelo Fiore among others. Very exciting stuff!

There was a big movement of "community singing" in the UK during the 1920s (mostly pushed by tory rags). They commissioned Novello and similar music publishers to make score compilations to support community sing-alongs. Today while charity shop perusing, I managed to get the Daily Express compilation (edited by John Goss!) and the News Chronicle compilation, and had a read through. Lots of scottish airs, some hymns and carols, a few american spirituals and folk songs, sea shanties and some British patriotic songs. Interesting charity shop find!

The expanded version of our 2024 paper has finally been published in the journal Information and Computation. This paper includes some of the work that lays the foundation for what I'm now doing with Kai Phan.

Da pacem Dómine, sustinéntibus te, ut prophétæ tui fidéles inveniántur: exáudi preces servi tui, et plebis tuæ Israel.

I sang again at St. Michael and all Saints in the morning where we sang Palestrina's Missa Brevis and Wesley's Wash me throughly:

Wash me throughly from my wickedness

And forgive me all my sin

For I acknowledge my faults

And my sin is ever before me

I also joined the choir at Old St. Paul's once again for Evensong and Benediction. We sang canticles by Harold Darke (both Magnificat and Nunc Dimittis), and an anthem by our own John Kitchen: Stand, Holy Cross, a setting of a text by Gordon Graham (link is to the livestream of the service):

Stand, Holy Cross, between my God and me

And cast a shadow where my heart can hide

Its frail mortality

From his perspicuous light.

The Cross's shade supplies my sin's disguise.

My soul protected, I can turn my eyes;

And now the Father’s light allows me view:

A world, my world, made new.

Then as horizons widen to a farther shore

And light on light enlightens more and more,

This larger vision brings a deeper peace

And sin and sorrow cease.

Stand, Holy Cross, between my God and me.

I said in my last post that proof interface still needed work for Holbert-ng to reach feature parity with Holbert 1, but being sick with COVID meant that suddenly pressing work commitments vanished and I stayed home to isolate myself. This gave me a lot of programming time, so now a preliminary release of Holbert-ng is imminent.

The real test will be to actually start writing my PL course notes (similar to my domain theory notes but more for an undergraduate PL theory course) with the proof assistant integrated throughout, as per my original vision. We're now almost at a point where that is a feasible thing to do. I will give a talk about some of my design decisions at the Wadler 70 event on Wednesday.

Coro's concert has now been officially announced. Please buy tickets as soon as you can! The venue is my usual All Saints Ainslie church so the acoustic is good but seating is limited. A particular favourite from the programme this time is Tallis' Lamentations of Jeremiah, which I love singing.

Iustus es Dómine, et rectum iudícium tuum: fac cum servo tuo secúndum misericórdiam tuam.

I am in Edinburgh this week for the combined LFCS/Plotkin/Wadler event so I stopped into my favourite church St. Michael and all Saints to sing in their choir for Mass today. We sang Darke's Mass in F (where I sang the tenor solo), chant propers (which I intoned) and Ola Gjeilo's Ubi Caritas. I linked to our performance in the livestream because SMAS's audio system is quite good and we sang it rather well I think.

Ubi cáritas et amor, Deus ibi est.	Where there is charity and love, there God is.
Congregávit nos in unum Christi amor;	The love of Christ has gathered us as one;
Exultémus et in ipso iucundémur;	Let us then exult and delight in him;
Timeámus et amémus Deum vivum,	Let us fear and love the living God,
Et ex corde diligámus nos sincéro.	And love each other with sincere hearts.
Ubi cáritas et amor, Deus ibi est.	Where there is charity and love, there God is.
Amen.	Amen.

I understand my usual choir at All Saints Ainslie sang Pitoni's Cantate Domino.

I also joined the choir at Old St. Paul's for Evensong and Benediction. We sang canticles by Attwood Walmisley (both Magnificat and Nunc Dimittis), and Wesley's anthem Lead me, Lord:

Lead me, Lord.

Lead me in thy righteousness.

Make thy way plain before my face.

For it is thou, Lord,

Thou, Lord, only,

That makest me dwell in safety.

While the proof interface is still very minimal, my students Josh Brown and Mio Wu have done some amazing work getting the reasoning core of Holbert-ng together. Because I am planning to talk about this work at WadlerFest in two weeks, I began finally to try to realise my original vision for this project and integrate the proof assistant into Forester itself.

It still has some rough edges, but, it works.

In particular, while it's not demonstrated by the above screenshot, proof and definition nodes can span multiple pages, have their own dependency graph (independent of Forester's), can appear in multiple pages, and have all of their state synced to local storage. It's very exciting and motivating to see this in action.

MIHI autem nimis honoráti sunt amíci tui, Deus: nimis confortátus est principátus eórum.
EGO autem sicut olíva fructificávi in domo Dómini, sperávi in misericórdia Dei mei: et exspectábo nomen tuum, quóniam bonum est ante conspéctum sanctórum tuórum.
Inclína Dómine, aurem tuam ad me, et exáudi me: salvum fac servum tuum, Deus meus, sperántem in te: miserére mihi, Domine, quóniam ad te clamávi tota die.

Today our choir at All Saints Ainslie sang for Evensong, so I sang my arrangement of Hildegard of Bingen's O Virtus Sapientiae with a psalm appended during the morning mass. The livestream can be found here:

O Virtus Sapiéntiæ	O Strength of Wisdom!
Quæ circúiens circuísti,	Thou who, circling, hast encircled
Comprehéndendo ómnia in una via quæ habet vitam.	Comprehending all things in the one way that hath life.
Tres alas habens:	Three wings thou hast:
Quarum una in altum volat,	The one which soareth on high,
Et áltera de terra sudat,	The other sweateth from the Earth
Et tértia úndique volat,	And the third flieth everywhere about.
Laus tibi sit, sicut te decet, O Sapiéntia.	Praise be to thee, as is meet, O Wisdom.

In between the morning mass and evensong, I began rehearsing for our next Coro concert. This meant I was singing at the church from morning to night!

For evensong, I selected the music but our normal director conducted. We sang Morley's fauxbourdon Magnificat and Nunc Dimittis, and Tallis' O Lord give thy Holy Spirit as the anthem.

O Lord, give thy Holy Spirit into our hearts,

And lighten our understanding,

That we may dwell in the fear of thy Name,

All the days of our life;

That we may know thee, the only True God:

And Jesus Christ, whom thou hast sent.

As I have previously mentioned, I'm on the PC of POPL this year. There were an unprecedented number of submissions (>600), which meant that even with reserve reviewers, each PC member ended up with 14 papers to review. Seeing as POPL papers are typically dense with a fair bit of maths, this is an extreme amount of work.

My workload was exacerbated by the fact that the Toronto paper matching system used by POPL seemed to produce ranks worse than random, so even before being assigned reviews I had to examine (at least the titles of) every submission to the conference to figure out what to bid on.

I don't think we want our PL and FM conferences to end up like AI conferences, with enormous PCs and an even higher volume of papers. I don't want our research to turn into a paper mill where we throw papers over the wall that even the reviewers barely read, let alone anyone else (at best, a disgusting AI summary might be all that is left of our papers for human consumption). But if things keep progressing this way, that's exactly where we'll end up — the volume of papers even in this iteration of POPL is such that I'm having to take shortcuts just to get the reviews done in time.

Normally, my policy is to write a review, wait a day (while not reading anything else), and then submit it, because often I will keep thinking about the paper while I go about my day. This PC membership has made that impossible.

Signum magnum appáruit in cælo: múlier amícta sole, et luna sub pédibus, et in cápite eius in coróna stellárum duodécim.
Gaudeámus omnes in Dómino, diem festum celebrántes sub honóre Maríaæ Vírginis: de cuius assumptióne gaudent Angeli, et colláudant Fílium Dei.

Our director was back from his trip today, so I returned to my deputy role at All Saints Ainslie. Today was a transferred Marian feast which ought to be called "The Assumption of the Blessed Virgin Mary" but due to our protestant-friendly lectionary it's watered down to a feast of "Mary the Mother". While I didn't direct it, I selected the anthem for this week, Stravinsky's Ave Maria:

Ave María, gratia plena, Dóminus tecum.	Hail Mary, full of grace, the Lord is with thee.
Benedícta tu in muliéribus et benedíctus fructus ventris tui, Jesus.	Blessed art thou among women, and blessed is the fruit of your womb, Jesus.
Sancta María, mater Dei, ora pro nobis peccatóribus,	Holy Mary, mother of God, pray for us sinners,
Nunc et in hora mortis nostræ. Amen.	Now and at the hour of our death. Amen.

In exchange for subjecting the congregation to a more unusual setting, I sang Schubert's Ave Maria (in Latin, to the same lyrics) at the end of the service.

We also had a choir management meeting yesterday to set priorities for the coming few months. Nothing firm to announce yet, but we might be bringing some new people into our team, which is very exciting.

I know I'm a bit of a broken record with the anti-LLM posting, but I recently read this excellent article from Katherine Rundell in the Guardian that was not only extremely compelling but also strangely gave me a bit of hope, or at least a call to action.

I talk a great deal about reading for pleasure; I’ve written elsewhere about the necessity of pleasure in the classroom, and why it is not an optional extra but the hallmark of true education. We must find ways to show children that reading gives you access to an inexhaustible source of delight. But I worry, too, that we are limiting the meaning of the word pleasure. Learning is a strange and discomfiting experience; it’s a struggle and a frustration, and epiphanies are rare. It is not always pleasure in its easiest sense.

So I think we also need to talk to young people about reading to outrun and outfight injustice. Reading to get faster, swifter and tougher; to develop powers of scrutiny and criticism and huge creative imagination. Reading human work to insist that we are human. Reading for liberation and emancipation; reading for intellectual freedom, and to have the strength to fight in the arenas of the mind, because when we let a computer think for us, we put a gun to the head of civilisation.

There are dark days ahead. If we are to fight against those with untold financial wealth, we will need untold intellectual wealth. We will need tough-minded people; people with stamina, a huge range of knowledge, and an ability to see wide and far enough to understand in real time what is being done to us. Reading for pleasure and delight are vital – but alongside that and even more urgently: reading for power.

Somehow I missed it that I got an award for my supervision last year. It slipped my mind completely until I got this certificate in my inbox:

Looking at the list of awardees, it seems any supervisor who was nominated was awarded such a commendation (except for the first-place winners). Thank you to whichever of my students nominated me!

Tibi dixit cor meum, quæsívi vultum tuum, vultum tuum Dómine requíram: ne avértas fáciem tuam a me.

I was once again the director of our choir at All Saints Ainslie, on a cold and wet Sunday with few choristers and few parishioners, even though it was a transferred feast. We sang Stopford's Do not be afraid, a poem by Gerard Markland based on the words of Isaiah:

Do not be afraid, for I have redeemed you.

I have called you by your name;

you are mine.

When you walk through the waters,

I'll be with you;

you will never sink beneath the waves.

When the fire is burning all around you,

you will never be consumed by the flames.

When the fear of loneliness is looming,

then remember I am at your side.

When you dwell in the exile of a stranger,

remember you are precious in my eyes.

You are mine, O my child,

I am your Father,

and I love you with a perfect love.

Do not be afraid, for I have redeemed you.

I have called you by your name;

you are mine.

There's something weird going on, because we celebrated the Transfiguration already on Quinquagesima Sunday, and last year they made no special observance of the feast of the Transfiguration. The transferring of feasts is such a mess! I'm liking Oliver Brewer-Lennon's policy of never transferring anything and celebrating feasts on the day more and more.

As part of Xin Lu's project we needed to come up with a version of CCS that supports explicit termination in the style of ACP. There is a paper by Luca Aceto and Matthew Hennessy which introduces a termination predicate, but they require that a nondeterministic choice P + Q is judged terminating (written P + Q \checkmark ) only when both P \checkmark and Q \checkmark . In other words, a process is only terminating if it has no choice but to terminate.

In our case, we want a judgement for possible termination, not guaranteed termination. So we had to come up with our own notions. We've formalised this in Isabelle, but what follows is the same but presented as Forester notes. Eventually, these notes may become part of another research notebook or even lecture notes.

You know the drill by now. Another article I read about the damage LLMs are doing to our intellectual pursuits. This is a deeply personal reflection from a mathematician, Kirwin Hampshire: The Dark Night of Mathematics.

There is nothing I can do. There may be nothing you can do. I have no prescriptions, policy recommendations, or coherent call to action. I just want to be honest and open about my emotional and spiritual response. I want to feel seen. I want folks like me to feel seen. I need the architects of our new mathematical paradigm to look me in the eye and acknowledge our shared humanity and soul before they deliver the coup de grâce. I need, most of all, for us to understand what we are really doing.

Deus in adiutórium meum inténde: Dómine ad adiuvándum me festína: confundántur et revereántur inimíci mei, qui quærunt ánimam meam.

I was once again the director of our choir at All Saints Ainslie, for the special Missing Persons Sunday today, with representatives from the Australian Federal Police present to offer special reflections and awareness about those who are missing in our territory and support their loved ones, many of whom were in attendance. We performed Rachmaninoff's Bogoroditse Devo:

Богородице Дево, радуйся,	Rejoice, virgin mother of God,
Благодатная Марие, Господь с тобою.	Mary, full of grace, the Lord is with you.
Благословена ты в женах,	Blessed are you among women,
и благословен плод чрева твоего,	and blessed is the fruit of your womb,
яко Спаса родила еси душ наших.	for you have borne the Saviour of our souls.

I've begun adding more to the material in my research notes on linear temporal properties. We've now covered the "top diamond" described in my note about my work with Kai Phan. Hope to add more this week!

Deus in loco sancto suo: Deus, qui inhabitáre facit unánimes in domo: ipse dabit virtútem et fortitúdinem plebi suæ.

I was once again the director of our choir at All Saints Ainslie, where we sang two anthems to a packed house: there were fourteen confirmees, and the bishop (and primate of Australia) came to induct them into the church. Our choir sang a favourite of mine, Lloyd's View Me, Lord, a lovely poem from Thomas Campion:

View me, Lord, a work of thine.

Shall I then lie drown'd in night?

Might thy grace in me but shine,

I should seem made all of light.

Cleanse me, Lord, that I may kneel

At thine altar, pure and white.

They that once thy mercies feel

gaze no more on Earth's delight.

Worldly joys, like shadows, fade

When the heav'nly light appears;

But the cov'nants thou hast made,

Endless, know not days nor years.

In thy word, Lord, is my trust;

To thy mercies fast I fly.

Though I am but clay and dust,

Yet thy grace can lift me high.

As well as Tallis' If ye love me, which, at least in my edition, was in the exact same key.

If ye love me, keep my commandments.

And I will pray the Father,

And He shall give you another comforter:

That He may bide with you forever, e'en the Spirit of Truth.

I also directed us for evensong, where we sang a mostly plainchant evensong, along with Stainer's Hail, Gladdening Light as usual, plus Vaughan Williams' The Call as an anthem (with solo verse sung by yours truly), from his settings of George Herbert poems, the Five Mystical Songs.

Come, my Way, my Truth, my Life;

Such a Way as gives us breath,

Such a Truth as ends all strife,

Such a Life as killeth death.

Come, my Light, my Feast, my Strength;

Such a Light as shows a Feast,

Such a Feast as mends in length,

Such a Strength as makes his guest.

Come, my Joy, my Love, my Heart;

Such a Joy as none can move,

Such a Love as none can part,

Such a Heart as joys in love.

We got back our student experience evaluations for our teaching in semester one. I'm pleased to report that I managed to bring Structured Programming from being one of the most unpopular courses in the university to one of the more liked, with 83% of respondents giving the thumbs up to the course and 95% to my teaching specifically, and no negative ratings. In particular, I was pleased that 100% of respondents indicated that I "treat students with respect".

I particularly was glad to read this comment:

Liam is an excellent communicator, educator, and convenor. He consistently takes time after his lectures to answer student questions and support them with the course content. His live coding is impressive, and he battles through IT issues without losing it, which is impressive in it's own right. His lectures are engaging and for those who attend I believe it to be an excellent learning experience. By doing crowd informed live coding he engages each of us in the process of solving the problem the first time, while he demonstrates the new concept. This leaves you feeling like you CAN do it. That the new concept isn't so alien, because you saw all the steps to build it. This is a huge confidence booster going into the lab, as now this is the second time you are trying to implement the concept, alone this time. He was quick to address student concerns on the forum and consistently asking students for feedback and suggested improvements. He showed genuine concern in the students that were struggling in the midsemester exams and adapted the course for their expressed needs. He is an excellent educator and I hope to take more of his classes in the future.

The ANU Logic Summer School is back again this year, and I will once again teach my ITP course. The timetable is not yet finalised, but I will likely not have to teach it all over two days as I did last year, which is a relief. It will likely run in the early days of December.

If you or your students have an interest in logic or verification, please consider sending your students! We also have some limited scholarships available.

Dóminus fortitúdo plebis suæ, et protéctor salutárium Christi sui est: salvum fac pópulum tuum, Domine, et bénedic hereditáti tuæ, et rege eos usque in sæculum.

Today I didn't attend my usual All Saints Ainslie as I was visiting Sydney, so I attended Christ Church St. Laurence instead. The choir was mens voices who sang the gregorian mass setting cum jubilo as well as The Call by Ralph Vaughan Williams, a setting of a poem by Herbert:

Come, my Way, my Truth, my Life:

Such a Way, as gives us breath:

Such a Truth, as ends all strife:

Such a Life, as killeth death.

Come, My Light, my Feast, my Strength:

Such a Light, as shows a feast:

Such a Feast, as mends in length:

Such a Strength, as makes his guest.

Come, my Joy, my Love, my Heart:

Such a Joy, as none can move:

Such a Love, as none can part:

Such a Heart, as joys in love.

It was a very restorative service, even for my (Buddhist) in-laws. I believe that my usual choir performed "Thee we adore" by T. Frederick H. Candlyn in my absence, an arrangement of adoro te devote.

Omnes gentes, pláudite mánibus, iubiláte Deo in voce exsultatiónis. Quóniam Dóminus excélsus, terríbilis: Rex mangus super omnem terram.

Today we were in light numbers at All Saints Ainslie but still pulled off a solid performance of How's Day by Day

Day by day, dear Lord,

of thee three things I pray;

to see thee more clearly,

to love thee more dearly,

to follow thee more nearly,

day by day.

This service included the baptism of many children all from the same family, so it was a rather special service in that respect. Later in the month we will have a confirmation service with fourteen (14!) confirmees, which is a promising sign for the health of the parish.

Ego autem sicut olíva fructificávi in domo Dómini, sperávi in misericórdia Dei mei: et exspectábo nomen tuum, quóniam bonum est ante conspéctum sanctórum tuórum.

As our director has started a UK tour with his secular singing ensemble, I have taken on the job of interim director at All Saints Ainslie, where we sang today Howell's My eyes for beauty pine:

My eyes for beauty pine,

My soul for Goddës grace:

No other care nor hope is mine,

To heaven I turn my face.

One splendour thence is shed

From all the stars above :

'Tis named when God's name is said,

'Tis Love, 'tis heavenly Love.

And every gentle heart,

That burns with true desire,

Is lit from eyes that mirror part

Of that celestial fire.

I think they transferred the feast of St. James to today rather than to the following Sunday (which is closer), because they want to focus the service next week on confirmations with the Bishop.

I quite enjoyed this article by Glyph. It pins down quite well what makes me somewhat concerned about the "autoformalisation" hype in the mathematics community. Mathematics has, up to now, considered all communication (beyond obvious cranks) to have some degree of good faith. The use of LLMs in mathematics have the potential to turn all of mathematics into an adversarial "find the flaw" game. I don't want to participate in an intellectual field like that.

I know I'm becoming a broken record in collecting anti-LLM articles and talking points, but it really is an article of faith for me.

My partner will be studying at the University of Canberra so I went on a little tour of their campus with her. There seems to be a mob of Kangaroos (is that the right collective noun?) that lives on the campus there. They are the grey Kangaroos that can be seen elsewhere in Canberra, but that doesn't stop the males from being intimidating both in size and musculature. I was also struck by how small the campus is in terms of buildings for the amount of space it occupies. A much smaller scale operation than the Australian National University seems to be.

NUNC scio vere, quia misit Dóminus Angelum suum: et erípuit me de manu Heródis, et de omni expectatióne plebis Iudæórum.

This morning at All Saints Ainslie I was the cantor for the morning mass, and with a soprano Cindy Chen (who was playing the organ for the other parts of the mass), we sang a 13th century English "gymel" piece, arranged by yours truly (I don't have a recording sadly):

Jesu Cristes milde moder stud biheld hire sone o rofe that he was ipined on.	Jesus Christ's mild mother stood and beheld her son on the rood that he was pinned on.
The son heng, the moder stud and biheld hire childes blud wu it of hise wundes ran.	The son hanged, the mother stood, and beheld her child's blood as it from his wounds ran.
Neue blisse he us broute that mankin so dere boute, and for us gaf is dere lif.	New blessings he to us brought, for mankind so dearly bought, and for us gave his dear life.
Glade and blithe thu us make, for thi swete sones sake, edi maiden blisful wif.	Glad and blythe thou us make, for thy sweet son's sake, noble maiden, blessed wife.
Quen of evene for thi blisse lithe al hure sorinesse and went hur yvel al into qud.	Queen of Heaven, for thy blessedness lightens all our sorrows and turns our evil all into good.
Bring hus, moder, to thi sonne, mak hus ever with him wone that hus boute wit this blud.	Bring us, mother, to thy son. Make us ever with him one, that he bought with this blood.
Amen.	Amen.

I returned to the church in the evening for Evensong. We sang Stainer's Hail, Gladdening Light as usual, as well as Phillip Moore's third service for the Magnificat and Nunc Dimittis. For anthem, we sang the first of Parry's Songs of Farewell, which we had previously performed at our recent concert: My soul there is a country

My soul, there is a country

Far beyond the stars,

Where stands a wingèd sentry

All skilful in the wars:

There, above noise and danger,

Sweet Peace sits crown'd with smiles,

And One born in a manger

Commands the beauteous files.

He is thy gracious Friend,

And—O my soul, awake!—

Did in pure love descend

To die here for thy sake.

If thou canst get but thither,

There grows the flower of Peace,

The Rose that cannot wither,

Thy fortress, and thy ease.

Leave then thy foolish ranges;

For none can thee secure

But One who never changes—

Thy God, thy life, thy cure.

I finished and marked the final exam for Structured Programming last week. I enjoyed teaching this course but I am very glad it's over. Perhaps surprisingly, considering the catastrophic results from my earlier exam, but the students in general did alright. Perhaps the poor performance shocked them into action somewhat and they practiced more. I also think I made the final exam a little gentler than the other assessments.

One thing that I regret doing, and will change in future iterations, is that the homework assignments (which I no longer trust as summative assessment, as they are solvable by LLM) did not have fixed due dates, but instead only recommended due dates before the exam/test for which they served as practice. The actual final due date was just at the end of semester, before the final exam I just marked. The result was, predictably in hindsight, that students didn't do the homework until the last minute, depriving them of the necessary programming practice before the midsession tests. We won't repeat this mistake.

Kai Phan has been building on her already very impressive result to produce a very nice picture of the monitorability landscape. I will present a brief summary of her results here, but eventually they will be incorporated into my research notebook on linear-time temporal properties. Mostly, our results concern the space of program properties — sets of program behaviours.

The classes of safety and guarantee above are the familiar closed and open sets respectively in the topology of program behaviours. In the above diagram, decision properties are the clopen sets — those sets that are both Safety properties and Guarantee properties, and obligation properties are, following Amir Pnueli, any boolean combination of closed or open sets.

Kai's original result was to show that all Bauer monitorable properties — that is, all properties for which a monitor can always potentially give an answer — cannot be distinguished from an obligation property by any monitor observing finite prefixes. What she has now done is prove that Bauer monitorable properties are exactly those properties that approximate an obligation property in this way. This led us to re-christen Bauer monitorability as the class of quasi-obligation properties. In a similar way, she has also identified the classes of quasi-safety and quasi-guarantee, which cannot be monitorably distinguished from safety and guarantee properties respectively, and proved that quasi-obligation properties are exactly those that are made up of boolean combinations of these.

At the bottom of the prism, we have another set of classes. What is commonly called weak monitorability sits at the very bottom — those properties for which there is at least one finite prefix that causes a monitor to give a definitive answer. We also have good monitorability and bad monitorability, which are those properties with at least one good or bad prefix respectively. It is easy to see that weak monitorability is the union of these classes. (Taking boolean combinations, as in the higher levels of the cube, leads to a trivial class containing all properties).

Kai has also now defined CTL characterisations for all of these lower classes, expressed as formulae over monitor trees, which we define reminiscent of Ghani, Hancock and Pattinson's stream processors. She then showed that the CTL formulae for all of the middle layer classes of the prism are obtained by wrapping the corresponding formula for the class below with \mathbf {AG}. For example, weak monitorability is defined as \mathbf {EF}\ (\mathit {yes} \lor \mathit {no}), and quasi-obligation is just \mathbf {AG}\ \mathbf {EF}\ (\mathit {yes} \lor \mathit {no}). Because of the aforementioned indistinguishability result (and because indistinguishable properties have indentical monitors), it's not possible to write CTL formulae for the top level of the prism, except for Decision properties (clopen sets) which correspond exactly to those monitors described by inductive trees — where all paths eventually terminate with an answer.

We're aiming to get this into ESOP or FoSSaCS this year. Hoping for the best! I think this is great work.

Dóminus illuminátio mea, et salus mea, quem timébo? Dóminus defénsor vitæ meæ, a quo trepidábo? Qui tríbulant me inimíci mei, infirmáti sunt, et cecidérunt.
Si iniquitátes observáveris Dómine, Dómine quis sustinébit? Quia apud te propitiátio est, Deus Israel.

Today at All Saints Ainslie we sang Palestrina's well-known Sicut Cervus:

Sicut cervus desíderat ad fontes aquárum:	Like as the hart desireth the waterbrooks:
ita desíderat ánima mea ad te, Deus.	So longeth my soul after thee, O God.

We didn't make any observation of the Sacred Heart, but that's not entirely unexpected for an Anglican parish, even a relatively spikey one.

Exáudi Dómine vocem meam, qua clamávi ad te: adiútor meus esto, ne derelínquas me neque despícias me, Deus salutáris meus.

Today at All Saints Ainslie we were in very reduced numbers — 1 to a part — but we sang Bob Chilcott's God so loved the world wonderfully!

God so loved the world

That he gave his only-begotten son

That whoso believeth in him should not perish

But have everlasting life.

Special thanks to Cindy Chen, our soprano soloist, and Mary-Anne Neilsen for stepping in and playing the organ at the last minute.

This week I attended (along with many others from ANU including Peter Höfner, Ali Nosherwan Hamed, Xin Lu, Kai Phan and Carlo Zancanaro) the yearly meeting of Formal Methods researchers in Australia at the University of Queensland. It was good to hear from colleagues again, and I was very impressed by the size of the group.

Peter Höfner also presented some of the initial thoughts and work around Yi Yao's PhD topic, and it was good to help clarify our thinking there. I think I will encourage all of my students not just to attend, but also to speak next year.

We encountered a kookaburra at breakfast that seemed determined to steal people's sausages (swooping right in front of them). This kookaburra seems to have absolutely no fear of humans, so I was able to get very close to take a picture. Eventually we saw it smashing a piece of bread against the table to "kill" it, as they do to lizards and snakes in more natural contexts.

This is a special edition of Church Music Corner where I share the programme for the second church choir concert of 2026, To the Soul's Quiet Harbour, continuing in the funerial theme established by our first concert. The student musicians from Burgmann Anglican School joined us at All Saints Ainslie to perform an afternoon of chamber music to a fairly full house. We sang pretty well despite being lopsided in numbers (I was the only tenor.)

The main works performed by the choir (interspersed by instrumental performances from Burgmann) were the first four of Parry's Songs of Farewell: My soul, there is a country, then I know my soul hath power, then Never weatherbeaten sail and There is an old belief. The last item of the concert was O How Amiable by Ralph Vaughan Williams, which we sung with pipe organ, choir, and instruments.

I think the concert went rather well. Thanks to all who put the effort in to make it possible, and to everyone that attended!

Respice in me, et miserére mei, Dómine: quóniam únicus et pauper sum ego: vide humilitátem meam, et labórem meum: et dimíte ómnia peccáta mea, Deus meus.
Cibávit eos ex ádipe fruménti, allelúia, et de petra, melle saturávit eos, allelúia, allelúia, allelúia.

Today at All Saints Ainslie we were in few numbers after our concert yesterday but we still managed to sing Tallis' Verily, verily I say unto you (link to my own recording I made last year):

Verily, verily, I say unto you:

Except ye eat the flesh of the Son of Man

and drink his blood,

ye have no life in you.

Whoso eateth my flesh,

And drinketh my blood,

Hath eternal life.

For my flesh is meat indeed,

and my blood is drink indeed,

He that eateth my flesh and drinketh my blood

Dwelleth in me, and I in him.

We didn't make any observation of the feast of Corpus Christi which I'm a bit unhappy about (but that's why we have at least got that Tallis anthem programmed).

I have been reading and digesting in pieces the new encyclical from Pope Leo XIV, Magnifica Humanitas. While in some places I feel it doesn't quite go far enough, and the Vatican has troubling connections to Anthropic, I think that the content of the encylclical itself is very good.

One of the things that I always believed even while I was an atheist was the infinite worth of human beings. This aspect that underpins much of Catholic social teaching has always been one of the things I agree with, and part of why I find artificial simulacra of human connection, human relationships, human personality or human creativity so offputting and spiritually uncomfortable.

The Pope's new writing really rams home this foundation of Catholic social teaching with reference to AI. It's not really an encyclical about AI, but rather using the issue of AI to introduce folks to this teaching of the church.

There is also the more profound and important level of ontological dignity. This is the dignity that belongs to every human being simply by virtue of existing, of having been willed, created and loved by God. No sin, failure, humiliation or exclusion can diminish the profound value of a human life that God has willed and called into being.

Another aspect of Christianity that I really like is that it embraces love as a relation. We must express and receive love for one another to experience God. Without acknowledging others, embracing and accepting others, and loving others, we cannot be any nearer to God. Simply meditating or looking within oneself may clarify one's thoughts but it cannot bring us to love. Understanding and accepting human life, in all its diversity, including all its joys and difficulties, as something to be loved and experienced rather than suppressed or even transcended is a part of the Christian view, and something that I really appreciate. It seems like Leo agrees:

Even when limitations are experienced as inner suffering, human wisdom teaches us not to deny or suppress it, but to integrate it. To eliminate suffering entirely would mean, in the end, extinguishing love and desire as well. Those who love and desire cannot avoid passing through trial and suffering; and over the years, we carry within us lessons that leave their mark like scars, the memories of a journey shaped by freedom and failure, dreams and disappointments. It is only thanks to the interplay of these elements that the wonders of the soul occur within us, allowing us to sense the richness of our humanity. To renounce this adventure, both tragic and splendid, in the name of a presumed transcendence of all limits, could mean many things, but it would no longer be human.

He touches on many more topics, and I strongly recommend folks take the time to read it. I'll finish by just quoting one passage that seems to be sending a lot of LLM-poisoned idiots on twitter into a tizzy, despite being obviously correct:

So-called artificial intelligences do not undergo experiences, do not possess a body, do not feel joy or pain, do not mature through relationships and do not know from within what love, work, friendship or responsibility mean. Nor do they have a moral conscience, since they do not judge good and evil, grasp the ultimate meaning of situations, or bear responsibility for consequences. They may imitate language, behavior and analytical skills, or even simulate empathy and understanding, but they do not understand what they produce, for they lack the affective, relational and spiritual perspective through which human beings grow in wisdom. Even when these tools are described as capable of “learning,” their way of doing so is different from that of a human person. It is not the experience of those who allow themselves to be shaped by life and grow over time through choices, mistakes, forgiveness and fidelity. Rather, it is a form of statistical adaptation based on data and feedback, which can be very effective, but does not imply inner growth.

Benedícta sit sancta Trínitas, atque indivísa Unitas: confitébimur ei, quia fecit nobíscum misericórdiam suam.
Caritas Dei diffúsa est in córdibus nostris, alleluia: per inhabitántem Spíritum eius in nobis, allelúia, allelúia.

Today at All Saints Ainslie our choir absolutely nailed the performance of William Byrd's beautiful and heartbreaking setting of Ave Verum Corpus

Ave verum corpus natum de María Vírgine,	Hail, true body, born of the Virgin Mary,
Vere passum immolátum in cruce pro hómine,	True suffering, sacrificed on the cross for Man,
Cuius latus perforátum unda fluxit sánguine,	From whose pierced side flowed waves of blood,
Esto nobis prægustátum in mortis exámine.	Be for us a foretaste in death's trial.
O dulcis, O pie, O Iesu fili Maríæ,	O sweet! O blessed! O Jesus, son of Mary,
Miserére mei, miserére mei, miserére mei.	Have mercy on me, have mercy on me, have mercy on me.

This Thursday is Corpus Christi, but I'm flying to Brisbane so I won't be able to make any observances this year, and Ainslie doesn't do anything in any case.

Also, this Saturday our choir is doing a concert with instrumentalists from the Burgmann Anglican School in Gungahlin.

The instrumentalists will perform a variety of pieces interspersing our performance of (the first four of) Parry's Songs of Farewell, finishing with us all performing some Ralph Vaughan Williams.

Do come down to All Saints Ainslie and support our music fund!

Spíritus Dómini replévit orbem terrárum, allelúia: et hoc quod cóntinet ómnia, sciéntiam habet vocis, allelúia, allelúia, allelúia.

Today at All Saints Ainslie the Choir was on for Evensong so our director Alasdair handled the music in the morning with our guest accompanist, Zac Hamilton-Russell. He sang Dering's Duo Seraphim with Zac's partner (whose name I now can't recall, sorry!) who has a lovely soprano voice! I stayed at the church all day reorganising our music, and because Alasdair and Zac had a recital until the late afternoon, I rehearsed and conducted the choir for Evensong. We sang Stainer's Hail, Gladdening Light as usual, as well as Phillip Moore's third service for the Magnificat and Nunc Dimittis. For anthem, we sang Hurford's Litany to the Holy Spirit:

In the hour of my distress,

When temptations me oppress,

And when I my sins confess,

Sweet Spirit, comfort me!

When I lie within my bed,

Sick in heart and sick in head,

And with doubts discomforted,

Sweet Spirit, comfort me!

When the house doth sigh and weep,

And the world is drown'd in sleep,

Yet mine eyes the watch do keep,

Sweet Spirit, comfort me!

It was a bit stressful as I wasn't planning to direct our choir but I did okay I think.

Also, the sermon by Oliver Brewer-Lennon from St. Michael and All Saints was brilliant as usual. He's the only priest whose (usually quite brief!) homilies I actually seek out and listen to, sometimes multiple times. Because my partner was curious, I translated it into Korean.

Our concert Radiant Dawn got a nice review in the local Canberra paper City News. You can read it here.

Mostly the review recapitulates the programme, but I'm glad that we "sung with emotional intensity and joyful celebration."

I do agree with the one commenter though:

Incredibly disappointing to see the program notes were written with AI.

I do know how this happened (things were prepared very much at the last minute), but I don't think it's an excuse. I'll have a word with Coro next time we run a concert to make sure this doesn't happen again.

I'm happy to report that the small grant I applied for with Charles Martin was successful. We will get a few thousand dollars to set up a teaching activity where students will program with punch cards again.

The key to this approach will be having only one card reading/program executing machine for all students, who must then book computer time just like in the old days of batch processing. I also thing there's something important about the physicality of punching holes in cards that students might appreciate. It's also LLM-proof programming, so there's that.

Today we had a cleaning bee at All Saints Ainslie where we cleaned up the organ loft and choir section of the church. It's a much nicer space to sing in now!

The choir has accumulated several musical treasures, one of which is an old but still decent edition of the original Church Anthem Book from Oxford, which I was allowed to take home with me. This impression is from 1954, but it was first printed in 1933. The successor book, the New Church Anthem Book, includes many of the same anthems but there are several (now added to my Music Index) anthems that are new to my collection.

Viri Galilæi, quid admirámini aspiciéntes in cælum? Allelúia: quemádmodum vidístis eum ascendéntem in cælum, ita véniet, allelúia, allelúia, allelúia.

Today at All Saints Ainslie we sang very well for Isom's King of all ages. I'm a bit disappointed that, unlike last year, we transferred the feast to the Sunday, though:

King of all Ages, throned on high,

Yet saviour too of those with faith,

Death at your onslaught died in fear,

And grace triumphant rules supreme.

Risen from death, the heav'nly Christ,

Receives from God the Father's hand,

Power over all created things,

A gift he could not know on Earth.

Then at your coming on the clouds,

With shining strength to be our judge,

Cancel the debt we owe you still,

Give back the glory we have lost.

Glory to you, O Christ our Lord,

Exalted far beyond our sight,

Reigning and forevermore,

with Father and with Paraclete.

I made a post on Mastodon that seemingly did numbers.

I don't know who needs to read this, but: there's value in doing things slowly, in your own way. Trying to maximise efficiency in your life is a fool's errand, and will just hurt you. Take the longer route with the nicer scenery. Write that email by hand instead of asking a bot to do it. Spend some time to read and not just skim. Take your time and cook a nice meal for yourself. Pursue little hobbies, even if you're not good at them. Don't compare yourself to others, don't focus on improving. Just enjoy every activity for itself. Don't let the world convince you that you always have to be optimising yourself. Just be sub-optimal and happy!

The reason I wrote this is because I read a thread on X (the everything app) which made my blood boil somewhat. Academics were saying that the reason they train students rather than just do research themselves with dreaded bots doing all the legwork is that there's value in the apprenticeship, in training a person. To me, that's a bad argument because it presupposes both that we should be prioritising efficiency above all else (definitely disagree) and that working with AI is more efficient in the long run than working with a student (also disagree but falsifiable).

I was devastated earlier this week when I marked the midsemester test for the first year course I'm teaching at the ANU. Less than one in five students passed the test, with more than half of submissions showing compile errors when running automatic tests on their code (this is for the second programming course in our programme, mind). My tutors completed the exam (100% correctly) in 25 minutes, and I gave my students 90 minutes.

I am fairly confident that this result is not a result of some deep failing on my part — I've taught first year students before with much better results — so I did a little digging to see how much students are engaging with my course. The results were not encouraging. More than half of students had not even started Homework 1, which came out at the beginning of semester (ten weeks ago), and fewer than one in five students had started Homework 2, which was directly intended to prepare them for the very test they failed. I hear reports from my tutors that students have begun education-defeating practices like copying a lab exercise into ChatGPT without even reading it.

This is all a symptom of the broader engagement crisis in teaching and an overall worrying decline in conscientiousness that is deeply troubling and bodes poorly for the future. Lecture attendance is extremely low. Usually I get no more than twenty students (out of about one hundred and twenty) in my lecture theatre. Frustratingly, it's precisely those students — the students I can actually reach — that I'm not worried about. When bad results come out like this, a lot of the relatively conscientious but struggling students begin to feel like they should give up and withdraw (and this pressure disproportionally affects under-represented groups such as female students). The rest of the semester has become a delicate morale balancing act where I need to shock students enough to get them to switch their brains on, but avoid demoralising students such that those who have ability but lack confidence are not discouraged.

I've retooled the remainder of the semester. We're going to do only the essentials in terms of more content. The rest will just be drilling exercises to help them gain the basic study skills they should already have by now. I'm so much more depressed and anxious running my course this way. I hope I can teach a 3rd year elective one day and be somewhat relieved of this.

I successfully performed in my first concert with Coro. I think it went very well, and I saw some familiar faces in the audience (including Fabian Mühlböck!). The programme was a very nice (although eclectic) collection of music spanning centuries. Some of my favourites included Lobo's Versa est in luctum, Stravinsky's Ave Maria, the Agnus Dei movements from all of Byrd's Masses, including the Byrd 5, and Morten Lauridsen's O Magnum Mysterium. It was a delight to sing with these talented singers and I'm looking forward to our next concert later in the year!

Vocem iucunditátis annuntiáte, et audiátur, allelúia: nuntiáte usque ad extrémum terræ: liberávit Dóminus pópulum suum, allelúia, allelúia.

Today at All Saints Ainslie I conducted a small group for the Crux Fidelis commonly (but almost certainly wrongly) attributed to John IV of Portugal (I took Neale's translation rather than a more direct one):

Crux fidélis, inter omnes	Faithful Cross, above all other,
Arbor una nóbilis:	One and only noble tree:
Nulla talem silva profert,	None in foliage, none in blossom,
Fronde, flóre, gérmine.	None in fruit thy peer may be.
Dulce lignum, dulci clavo,	Sweetest wood and sweetest iron,
Dulce pondus sústinens.	Sweetest weight is hung on thee.

I'm in a bit of a pickle, although I accept it sounds like an academic "first-world problem": I already have three first year PhD students (Yi, Kai and Xin) that I supervise quite actively. I still have funding for one more international place and I'm currently talking to four additional people who want to do a PhD with me, some of whom are local students so very likely to get funding. The worry is twofold:

1. I'm starting to run out of good topic ideas to help possible students get started on a proposal, and
2. I don't think I'm capable of supervising many more students, at least not in their first year. Once my existing students are further along it might be easier.

I am worried that I might have to start turning good people down — although I don't want to. But I fear that if I accept too many students the outcome will be worse for all of us.

Cantáte Dómino cánticum novum, allelúia: quia mirabília fecit Dóminus, allelúia: ante conspéctum géntium revelávit iustítiam suam, allelúia, allelúia.

Today at All Saints Ainslie we reprised Goss' anthem O Saviour of the World from our concert earlier in the year:

O Saviour of the world,

who by thy Cross and precious Blood

hast redeemed us:

Save us, and help us,

we humbly beseech thee, O Lord.

Amen.

After that I had a rehearsal with Coro for our upcoming concert, Coro Concert: Radiant Dawn. Please buy tickets and come along!

My student Kai Phan was absolutely on fire this week. About five times I threw out a few idle conjectures I had, and within hours she'd come back with a proof or a counterexample. We made more progress in one week than I had thinking about this stuff for months.

It's well known in the world of runtime verification that the class of monitorable properties (by which I mean the definition used by Bauer, where no monitor will get into an "ugly" state where no informative answer is possible) is larger than the set of safety or guarantee properties, or their boolean combinations (called obligation properties or \Delta _2).

What Kai showed recently is that all monitorable properties are indistinguishable by any monitor from an obligation property. This shows that a lot of the monitorability classes we find in the literature are making a distinction from standard sets in \Delta _2 that is only observable at infinity anyway. So the "largeness" of the monitorability classes is illusory, and obligation properties are all you need.

The proof has been mechanised in Isabelle/HOL, and we have a number of other supporting contributions that I think will make a good paper for POPL or LICS. I'm very proud of Kai's progress so far! I think this result will reinforce her plan for her thesis, which is to semantically tackle revocable monitors (i.e. monitors that can change their mind). Seeing as the difference hierarchy is contained at all finite levels in \Delta _2, we should have an easy time justifying restricting to \Delta _2 properties now.

Coro's concert has now been officially announced. Please buy tickets as soon as you can! The venue is my usual All Saints Ainslie church so the acoustic is good but seating is limited.

Coro, one of Canberra's leading choral ensembles and two-time Canberra Critics' CIrcle Award recipient, invites audiences to experience Radiant Dawn: From Lamentation to Light, an extraordinary hour of choral music that traces the path from sorrow and supplication to renewal, wonder, and radiant joy.

This thoughtfully curated program - the ensemble's first for 2026 - brings together masterpieces from the Renaissance and the modern era, revealing how composers across centuries have responded to the deepest human emotions with beauty, faith, and hope.

Beginning in stillness and grief with three great sacred works of the Renaissance by Handl, Victoria, and Lobo, these works explore mortality, sorrow, and the search for consolation. Yet from darkness emerges hope. William Byrd’s three exquisite settings of the Agnus Dei — for three, four, and five voices — chart a journey from intimate simplicity to glorious fullness of sound. Interwoven are Igor Stravinsky’s luminous Ave Maria and Claude Le Jeune’s joyful Revecy venir du printemps, suggesting grace, renewal, and the first stirrings of life.

At the centre of the evening, and giving the concert its title, stands James MacMillan’s breathtaking O Radiant Dawn, a contemporary choral masterpiece of glowing sonorities and spiritual intensity.

Celebrating life with energy, intimacy and warmth, the afternoon closes with works by Finzi and Chilcott, followed by Morten Lauridsen’s beloved O Magnum Mysterium.

Radiant Dawn: From Lamentation to Light is a concert of striking contrasts and deep emotional resonance — music that journeys through shadow into brilliance, reminding us of the enduring power of the human spirit.

Misericórdia Dómini plena est terra, allelúia: verbo Dei cæli firmáti sunt, allelúia, allelúia.

Today at All Saints Ainslie I was planning to sing Dering's Duo Seraphim as a duet with our choir director but he was exhausted and unable to come in for the morning mass, so instead I sang some Gregorian chants, specifically the introit for this Sunday in Latin (text above), the Easter Sequence in English using an older translation I remember from St. Mary's Cathedral (text below), and then the introit for last sunday:

Christians to the Paschal victim offer sacrifice and praise.

The sheep are ransomed by the Lamb;

And Christ, the undefiled, hath sinners to his Father reconciled.

Death and life contended, combat strangely ended:

Life's own champion slain, yet lives to reign.

Tell us, Mary, what thou didst see upon the way.

The tomb the living did enclose, I saw Christ's glory as he rose.

The angels attesting, shroud with graveclothes resting.

Christ my hope has risen! He goes before you into Gallilee.

That Christ is truly risen from the dead we know.

Victorious King, thy mercy show. Amen. Alleluia.

After that we had choral evensong for this month, this time directed by our usual director. We sang Stainer's Hail, Gladdening Light as usual, as well as Phillip Moore's third service for the Magnificat and Nunc Dimittis (it's hard to find good recordings). Because it was the day after Anzac Day, we also sang Daley's In Remembrance.

Do not stand at my grave and weep;

I am not there, I do not sleep:

I am a thousand winds that blow,

I am the diamond glint on snow,

I am the sunlight on ripened grain,

I am the gentle morning rain.

And when you wake in the morning's hush,

I am the sweet uplifting rush

Of quiet birds in circled flight.

I am the soft stars that shine at night.

Do not stand at my grave and cry,

I am not there, I did not die.

Today we had our regular PhD monitoring event, where all students and faculty in the Foundations cluster go to a remote location for a day, listen to some talks, and hold interviews with students where we ensure they're well supported. We also try to run some fun activities and get the students socialising with each other. It's always an enjoyable day.

This time we had a fairly packed schedule and many students to get through, so I didn't get any time to play frisbee, although I did take a few nice shots of the landscape around the Cuppacumbalong Homestead where we held our event.

I met a few students who were new to me and had a few stimulating research discussions, and my students Kai Phan, Xin Lu and Yi Yao got to know each other and other students a bit better. The day was quite a success, I think.

Iubiláte Deo omnis terra, allelúia: psalmum dícite nómini eius, allelúia: date glóriam laudi eius, allelúia, allelúia, allelúia.

Today at All Saints Ainslie our director Alasdair was our ad-hoc organist as we sang Mozart's Ave Verum Corpus:

Ave verum corpus natum de María Vírgine;	Hail, true body, born of the Virgin Mary;
Vere passum, immolátum in cruce pro hómine;	True suffering, sacrificed on the cross for Man;
Cuius latus perforátum unda fluxit et sánguine	From whose pierced side flowed waves of blood,
Esto nobis prægustátum in mortis examine.	Be for us a foretaste in death's trial.

After the mass I had my first rehearsal for the upcoming Coro concert. It was very productive. One piece of repertoire that really stuck with me was the Stravinsky Ave Maria, which I'd not heard before.

I have made significant additions to my research notes on Linear-time temporal properties. Now I have all the relevant content from Defining Liveness, and some of the definitions that will appear in the forthcoming journal paper from me and Rayhana Amjad. This paper finally got reviews back, and we have quite a few things to do but I'm confident we'll get there.

My students Mio Wu and Josh Brown have been doing some great work on the next generation of the Holbert proof assistant. In particular, Josh has now implemented a pluggable term structure, allowing various types of terms, each with their own unification methods and structure definitions, to be combined together in judgements. Mio is confident she can generalise his approach to work for higher order terms as well, which is very exciting.

As part of my general desire to stop using anything that feeds the LLM bots, I am gradually beginning to migrate off of GitHub. Fortunately the Holbert-NG crew are also happy to leave GitHub, so we are going to move to tangled for the time being.

I also got the chance to do some programming work myself. Soon we should have a similar proof UI to what the original Holbert has. I think most of the architecture is in place now.

Quasi modo géniti infántes, allelúia: rationábile, sine dolo lac concupíscite, allelúia, allelúia, allelúia

Today at All Saints Ainslie we had small numbers (I was the only tenor) but sang well for Walford Davies' Blessed are the pure in heart:

Blessed are the pure in heart,

For they shall see our God.

The secret of the Lord is theirs,

Their soul is Christ's abode.

Still to the lowly soul

He doth himself impart,

And for his dwelling and his throne

Chooseth the pure in heart.

Unfortunately we were plagued once again with sound system gremlins today. I'm honestly sick of it, the speakers and microphones are always barely working or not working. Apparently fixing it properly would cost tens of thousands of dollars the parish doesn't have. I don't know what can be done, but it's very frustrating.

Part of my job as an educator is to create situations where my students will be stressed, they will struggle, they might get frustrated, they might even hate me (although that's rare). My mentor Kai Engelhardt said that part of his job was to "torture students". It's a joke of course but there is a kernel of truth there: particularly for learning skills like debugging, there's no better way to learn than by trying to reason your way out of a buggy mess of your own creation. Inflicting this kind of stuff on students is actually kind of essential to education.

A lot of students these days are totally unused to feeling stuck. I asked my Structured Programming students who failed my midterm test the other week how they studied. Many of them actually did quite a lot of practice! But the moment they encountered a bug they couldn't immediately fix, they turned to the bots to solve their problem for them. They read and understood what the bot did, and they conflated that with being able to do it themselves.

Part of the reason these bots are hurting education because they undercut my ability to inflict (educational, non-excessive) stress on my students. I used to design effective programming courses that would keep the stress levels low enough to avoid demoralising students but high enough that they had to engage and work and learn. Now if stress levels go over a certain (low) threshold, all the work gets done by AI unless it's in an invigilated exam, which I used to avoid because they're stress spikes. I don't have a good solution. Just very unhappy.

I found this excellent mastodon thread where someone was brave enough to have a look at the leaked Claude Code source code. Anthropic proudly boasted that much of Claude Code was written by Claude Code — and it definitely shows, and not in a good way. One of the most atrocious code bases I've ever seen. I guess they anticipate going out of business before they have to maintain this crap.

Dómine ne longe fácias auxílium tuum a me, ad defensiónem meam áspice: líbera me de ore leónis, et a córnibus unicornuórum humilitátem meam.

For the first three ferias of Holy Week, I sang gregorian chants (mostly various lenten introits) for the introit and recessional of our contemplative evening masses at All Saints Ainslie. On the Wednesday, I was joined by Lynda Tooth on piano and we performed Dowland's In this trembling shadow:

In this trembling shadow, cast

From those boughes which thy winds shake

Farre from humane troubles plac’d

Songs to the Lord would I make

Darknesse from my minde then take

For thy rites none may begin

Till they feele thy light within.

Nos autem gloriári opórtet, in cruce Dómini nostri Iesu Christi: in quo est salus, vita et ressuréctio nostra: per quem salváti, et liberáti sumus.
Adorámus te, Christe, et benedícimus tibi, quia per crucem sanctam tuam redemísti mundum.

The triduum at All Saints Ainslie consisted just of two main services: the Mass of the Lord's Supper on the Thursday night, followed by the Liturgy of the Passion the following morning. On Thursday we sang I Give You a New Commandment by Nardone during the foot washing:

I give to you a new commandment;

A new commandment I give to you:

That you love one another,

Love one another as I have loved you.

(Ubi cáritas et vera, Deus ibi est)

(Congregávit nos in unum Christi amor)

(Exultémus et in ipso iucundémur)

(Timeámus et amémus Deum vivum.)

(Et ex corde diligámus nos sincéro.)

Amen.

As well as Duruflé's Ubi Caritas during communion, with a very similar but slightly different text:

Ubi cáritas et amor, Deus ibi est.	Where there is charity and love, there God is.
Congregávit nos in unum Christi amor;	The love of Christ has gathered us as one;
Exultémus et in ipso iucundémur;	Let us then exult and delight in him;
Timeámus et amémus Deum vivum,	Let us fear and love the living God,
Et ex corde diligámus nos sincéro.	And love each other with sincere hearts.
Ubi cáritas et amor, Deus ibi est.	Where there is charity and love, there God is.
Amen.	Amen.

We weren't high church enough to do a proper Eucharistic procession, but there was a stripping of the altar afterwards with the recitation of Psalm 22. St. Michael and All Saints showed us how it's done with procession, veneration, stripping of the altar, the cleaning of the altar with water and wine, then Fr. Oliver Brewer-Lennon dramatically threw aside the brush used to clean the altar, smashed the old Paschal candle on the sanctuary steps, locked shut the sanctuary gates, tied them with his stole, and ran away (cf. Matthew 26:56), plunging the church into darkness.

The following Good Friday liturgy consisted primarily of the veneration of the Cross and the distribution of the Eucharist which was consecrated the night before. For veneration, we sang first the Victoria Reproaches:

O my people, what have I done to you?

Or in what way have I offended you?

Answer me.

Ἅγιος ὁ Θεός, Holy God,

Ἅγιος ἰσχυρός, Holy and Strong,

Ἅγιος ἀθάνατος, ἐλέησον ἡμᾶς.

Holy and Immortal One, have mercy upon us.

Then we sang Leighton's Solus ad Victimam:

Alone to sacrifice thou goest, Lord,

Giving thyself to death, whom thou hast slain.

For us thy wretched folk is any word?

Who knew that for our sins this is thy pain?

For they are ours, O Lord, our deeds,

Why must thou suffer torture for our sins?

Let our hearts suffer in thy Passion, Lord,

That very suffering may thy mercy win.

This is the night of tears, the three days' space.

Sorrow abiding in the eventide,

Until the daybreak with the risen Christ,

And hearts that sorrowed shall be satisfied.

So may our hearts share in thine anguish, Lord,

That they may sharers of thy glory be;

Heavy with weeping may the three days pass,

To win the laughter of thine Easter Day.

During the distribution of communion we sang O vos omnes from Victoria's Tenebræ responsories.

O vos omnes qui tránsitis per viam,	O all you people that travel by this road,
Atténdite et vidéte!	Look and see
Si est dolor símilis, sicut dolor meus.	Whether there is any sorrow like my sorrow.
Atténdite, univérsi pópuli et vidéte dolórem meum	Look, all you people, and see my anguish.
Si est dolor símilis, sicut dolor meus.	Whether there is any sorrow like my sorrow.

RESURREXI, et adhuc tecum sum, allelúia: posuísti super me manum tuam, allelúia: mirábilis facta est sciéntia tua, allelúia, allelúia.

For Easter this year the church at All Saints Ainslie was filled with flowers, which was lovely. We had a vigil service at night followed by a service in the morning. Sadly the Vigil service didn't include a litany, but we sang Holy is the True Light at the vigil:

Holy is the True Light, and passing wonderful,

Lending radiance to them that endured

In the heat of the conflict.

From Christ they inherit a home of unfading splendour,

Wherein they rejoice with gladness evermore. Alleluia!

We also sang the Easter inaugural Gloria from the Darke Mass in F, both in the vigil and the Sunday Mass.

For the Sunday Mass we sang Ouseley's From the Rising of the Sun:

From the rising of the sun

To the going down of the same,

My Name shall be great among the Gentiles,

And in ev'ry place incense shall be offer'd up unto my Name:

For My Name shall be great among the heathen,

Thus saith the Lord!

I was also given the honour and privilege to once again proclaim the resurrection during the vigil, video below. This chant is my own version by expurgating some bits from the Roman Missal for length. I got a lot of compliments afterwards; although I can detect a few wobbly notes, I think my delivery is improved compared to last year.