If $X=\text{Spec}(A)$ where $A$ is a domain, then $\mathcal{O}_X(U)=\bigcap_{p\in U}A_p$
Posted by rmdmc89, at math.stackexchange.com,
I'm trying to prove the following: If $X=\text{Spec}(A)$ where $A$ is a domain, then $\mathcal{O}_X(U)=\bigcap_{p\in U}A_pā¦