Relations and Functions

The topic of relations and functions is central in all mathematics and computing. In the former, whether it is calculus, algebra or theory of computation, one deals with relations (notably equivalence relations, order) and all sorts of functions while in the latter one computes relations and functions (among other related endeavours), in that, one writes programs that given an input to a relation they compute the response (true or false) or given an input to a function they compute a response which is some object (number, graph, tree, matrix, other) or nothing, in case there is no response for said input (for example, there is no response to input “x, y” if what we are computing is \(\frac{\displaystyle x}{\displaystyle y}\) but \(y=0\) ).