MATH.16:8 - Common Anti-Patterns and How to Avoid Them

Recovery mistaken for full determination. Take A=B={0}. Recovering both components from A x B x {0,1} works, but forming an element also requires choosing 0 or 1. If only A and B should determine the result, require the unique combining map. If the extra choice is useful, name it as part of the input.

Compatible components processed incompatibly. A map on each component need not preserve their agreement. Test the equation in :4.4; the one-component increment in :5.1 supplies a failing case and its repair.

A familiar encoding chosen before its use. A pair and a tagged alternative support different functions. Recover the intended formation and processing operations before selecting either.