I am a 9th grader self-studying about set theory and functions. I understood most basic concepts, but I didn't understand what is a surjective function. I have understood what is an injective funct...

On topic: Surjective means that every element in the codomain is "hit" by the function, i.e. given a function f: X → Y f: X → Y the image im(X) i m (X) of f equals the codomain set Y Y. To prove …

What you're trying to prove is that surjectivity is stable under base change, not that it is local on the target.

Aug 14, 2019 · I use the fact that a composition of injections is injective and a composition of surjections is surjective. I also use the definition of finite where injective $\iff$ surjective within …

Oct 29, 2020 · Wikipedia uses this picture for injective and surjective functions. The top right is non-surjective. I have added a mapping on, is this now surjective? Why/why not?

Update: In the category of sets, an epimorphism is a surjective map and a monomorphism is an injective map. As is mentioned in the morphisms question, the usual notation is …

11 The statement that section maps are not always surjective for surjective map of sheaves is equivalent to non-exactness of the functor of global sections — or equivalently, to non-triviality …

Mar 30, 2020 · A function that is not surjective means that f: Z → Z f: Z → Z means f f maps to some of Z Z but not all. Can you think of any examples? What about a function that maps to …

Oct 24, 2020 · For Banach spaces $X$ and $Y$, a bounded operator $A: X\to Y$ is also bounded below iff the adjoint $A^*: Y^*\to X^*$, defined as $A^*: f\mapsto f\circ A$, is surjective.

Proving functions are injective and surjective Ask Question Asked 11 years, 9 months ago Modified 11 years, 9 months ago