Question

A function f: A→B is said to be one-to-one if, and only if:

Answer 1

Answer:

Definition. A function f : A → B is one-to-one if for each b ∈ B there is at most one a ∈ A with f(a) = b. It is onto if for each b ∈ B there is at least one a ∈ A with f(a) = b. It is a one-to-one correspondence or bijection if it is both one-to-one and onto.

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