If g∘f is injective, so is f

ProofInjective and surjective functions

Let $f\colon A \to B$ and $g\colon B \to C$ be functions. Prove that if $g \circ f$ is injective, then $f$ is injective.

Write your proof in plain text. Put math between dollar signs, like $x^2 \ge 0$ .

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If g∘f is injective, so is f · Proofwise

ProofInjective and surjective functions

Let $f\colon A \to B$ and $g\colon B \to C$ be functions. Prove that if $g \circ f$ is injective, then $f$ is injective.

Write your proof in plain text. Put math between dollar signs, like $x^2 \ge 0$ .

Your formatted proof appears here.