prove that a set S is infinite if and only if there is a proper subset A of S and a ibjection between A and S

prove that a set S is infinite if and only if there is a proper subset A of S and a ibjection between A and S

Functions:Suppose there are two non-empty sets . A function f from is assigning exactly one element of B to each element of A.It is denoted by Consider the statement given in the statement;...