How to prove that $f$ surjective, if $g$ is injective and $g \circ f$ is surjective?
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$g\circ f$ is Surjective and $g$ is Injective then Prove that $f$ is surjective
125644
How to check f is surjective
97605
Let $f$ be a surjective homomorphism. Prove that $\ker(f)$ is a maximal ideal
6023
Surjectivity of Composition of Surjective Functions
144589
Proving that if $f(x) \le g(x)$ then $f(x_0) \le g(x_0)$
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proof verification: If $f:G \rightarrow H$ is group homomorphism, and $H$ is abelian, then $G$ is abelian
63836
Show there exists $g:(0,1)\to\mathbb{R}^2$ such that $h\circ g$ constant, $g$ continuously differentiable and $g$ injective
126065
Example $g\circ f=id_A$ but $f\circ g\neq id_B$
146356
To prove two sets are isomorphic is it sufficient to find 2 injections or 2 surjections?
133083
Injectivity and surjectivity of a recursive function
22061
$|f(x)-f(y)|\geq k|x-y|$.Then $f$ is bijective and its inverse is continuous.
74657
Can this intuition give a proof that an isometry $f:X \to X$ is surjective for compact metric space $X$?
14994
Showing a function $f$ cannot be surjective
46629
Prove if $f(x) = g(x)$ for each rational number x and $f$ and $g$ are continuous, then $f = g$
73047
Proving surjectivity of $\cos(z)$ and $\sin(z)$ and find all $z : \cos(z) \in \mathbb R$ and all $z: \sin(z) \in \mathbb R$
98816
How to prove that $\{f+g<a\}=\bigcup_{r\in{\Bbb Q}}(\{f<r\}\cap\{g<a-r\})$?
96202
Prove composition of bijections is bijection