Show/Prove that if f: X → Y is one-to-one on X, and A subset of X, then f^-1(f(A))<= subset A.(adsbygoogle = window.adsbygoogle || []).push({});

If you wouldn’t mind, please check whether I did it correctly. Thanks in advance.

Suppose x Є A

Then, f(x) Є f(A)

By image function y =f(x)

Thus, y = f(x) Є f(A)

And by inverse image, f^-1(y) = f-1(f(x)) Є f^-1(f(A)) <= subset A

Therefore: Є f^-1(f(A)) <= subset A.

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# Abstract/Discrete/Algebraic Mathematics.

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