[tex]A_0 \subset f^{-1} (f (A_0)) [/tex](adsbygoogle = window.adsbygoogle || []).push({});

This inclusion is an equality if f is injective.

What I can't understand is how it is even defined iffisn't a bijection. If it is not a bijection, then there is no inverse function. Is there?

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# Question Regarding Sets and Functions

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