Here's the problem:
Let X and Y be sets. Let f: X --> Y, and let A be a subset of Y.
Prove that f(f-1(A)) is a subset of A.
Any help is much appreciated!
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Here's the problem:
Let X and Y be sets. Let f: X --> Y, and let A be a subset of Y.
Prove that f(f-1(A)) is a subset of A.
Any help is much appreciated!
I think it might be
f(f^-1(A)) = f(x) is an element of X such that f(x) is an element of f(A).