Editing Bijective proof (section)

{{Short description|Technique for proving sets have equal size}}
In [[combinatorics]], '''bijective proof''' is a [[mathematical proof|proof]] technique for proving that two sets have equally many elements, or that the sets in two [[combinatorial class]]es have equal size, by finding a [[bijective function]] that maps one set one-to-one onto the other. This technique can be useful as a way of finding a formula for the number of elements of certain sets, by corresponding them with other sets that are easier to count. Additionally, the nature of the bijection itself often provides powerful insights into each or both of the sets.