# No indentation after theorem environment with amsthm

I use the amsthm package and dont want lines which start right after the theorem environment to be indented. I consulted the manual of the package and it said to define a new theorem style. I expected the following MWE to accomplish this task.

\documentclass[12pt,a4paper]{scrreprt}

\usepackage{amsthm}
\newtheoremstyle{abcd}% name
{}%      Space above, empty = usual value'
{}%      Space below
{\itshape}% Body font
{}%         Indent amount (empty = no indent, \parindent = para indent)
{\bfseries}% Thm head font
{.}%        Punctuation after thm head
{.5em}% Space after thm head: \newline = linebreak
{}%         Thm head spec
\theoremstyle{abcd}

\newtheorem{defn}{Definition}
\begin{document}
\begin{defn}
Some defintion
\end{defn}
This sentence shouldn't be indented.
\end{document}


However, I end up with this

That is what I would expect (obtained using a noindent right after the theorem environment ends)

-
I expect a definition to be a paragraph of its own, so the following one should be indented. –  egreg May 8 at 13:16

\documentclass[12pt,a4paper]{scrreprt}
\usepackage{amsthm}
\usepackage{etoolbox}

\newtheorem{defn}{Definition}
\AfterEndEnvironment{defn}{\noindent\ignorespaces}

\begin{document}
\begin{defn}
Some definition.
\end{defn}
This sentence isn't indented.
\end{document}
`

However this goes against intuition; the sentence after a definition (or any other theorem-like structure) logically starts a new paragraph, so its first line should be treated as any other first line of a new paragraph.

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This works as intended, thank you. –  user17410 May 8 at 13:43