I have the following problem:
Let $X$ be a scheme and $x$ a closed point on it. If $F$ is a sheaf on X with nontrivial stalk $F_x$ at $x$, then one has a canonical surjective morphism $F\rightarrow G$, where $G$ is the structure sheaf of the point $x$. I dont understand how to describe $G$ and where this morphism comes from and why it should be surjective. Perhaps one can explain that in detail for me.
Thank you very much