replace \fG

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Maximilian Keßler 2022-02-16 02:09:06 +01:00
parent 915683c2c3
commit 098b35e359

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@ -2329,13 +2329,13 @@ If $P_e $ with $e < d$ was $\neq 0$, it could not be a multiple of $P$ contradic
\subsubsection{Examples of sheaves} \subsubsection{Examples of sheaves}
\begin{example} \begin{example}
Let $G$ be a set and let $\fG(U)$ be the set of arbitrary maps $U \xrightarrow{f} G$. We put $r_{U,V}(f) = f\defon{V}$. Let $G$ be a set and let $\mathfrak{G}(U)$ be the set of arbitrary maps $U \xrightarrow{f} G$. We put $r_{U,V}(f) = f\defon{V}$.
It is easy to see that this defines a sheaf. It is easy to see that this defines a sheaf.
If $\cdot $ is a group operation on $G$, then $(f\cdot g)(x) \coloneqq f(x)\cdot g(x)$ defines the structure of a sheaf of group on $\fG$. If $\cdot $ is a group operation on $G$, then $(f\cdot g)(x) \coloneqq f(x)\cdot g(x)$ defines the structure of a sheaf of group on $\mathfrak{G}$.
Similarly, a ring structure on $G$ can be used to define the structure of a sheaf of rings on $\fG$. Similarly, a ring structure on $G$ can be used to define the structure of a sheaf of rings on $\mathfrak{G}$.
\end{example} \end{example}
\begin{example} \begin{example}
If in the previous example $G$ carries a topology and $\mathcal{G}(U) \subseteq \fG(U)$ is the subset (subring, subgroup) of continuous functions $U \xrightarrow{f} G$, then $\mathcal{G}$ is a subsheaf of $\fG$, called the sheaf of continuous $G$-valued functions on (open subsets of) $X$. If in the previous example $G$ carries a topology and $\mathcal{G}(U) \subseteq \mathfrak{G}(U)$ is the subset (subring, subgroup) of continuous functions $U \xrightarrow{f} G$, then $\mathcal{G}$ is a subsheaf of $\mathfrak{G}$, called the sheaf of continuous $G$-valued functions on (open subsets of) $X$.
\end{example} \end{example}
\begin{example} \begin{example}