The following code
\documentclass{scrbook}
\usepackage{amsthm}
\newtheorem{theo}{Theorem}
\begin{document}
\begin{theo}
Rhabarber Rhabarber Rhabarber Rhabarber
\begin{enumerate}
\item Rhabarber Rhabarber
\item Rhabarber Rhabarber
\end{enumerate}
\end{theo}
\begin{proof}
\begin{enumerate}
\item Rhabarber Rhabarber
\item Rhabarber Rhabarber
\end{enumerate}
\end{proof}
\end{document}
produces
The distance between "Proof." and "1. Rharbarber..." (marked with a red rectangle) is too great for my liking. How can I shorten it?

amsthmdocumentation --texdoc amsthm(you must have a fairly recent installation of tex live; documentation was updated in april 2015). the answer is on p.5, and although it is presented with respect to theorems, the same approach should work with a proof. – barbara beeton Jul 18 '16 at 21:51