Definition. \times operation for retraction pairs [dt-005J]

Given two retraction pairs (f,g) and (h,i), our retraction pair for their product is just the product of their embedding and projection, i.e. (f \times h, g \times i), using our product operation on continuous functions: \dfrac {A \xtofrom [g]{f} B\quad C \xtofrom [i]{h} D}{A\times C \xtofrom [g \times i]{f \times h} B \times D}