Extra period in section labels after redefinition of \theparagraph

Question

I want the paragraphs in my document numerated with lowercase letters, followed by a period. So I added the line \renewcommand{\theparagraph}{\alph{paragraph}} to my document which created the numbering I wanted. A side effect of this was however that periods also appeared after the Chapter/Section/Float numbers in their label (but not their reference!).

MWE:

\documentclass{scrartcl}
\renewcommand{\theparagraph}{\alph{paragraph}}
\setcounter{secnumdepth}{4}

\begin{document}
\section{Foo}\label{sec:foo}
\ref{sec:foo}
\paragraph{Bar}\label{sec:bar}
\end{document}

produces:

I noticed that this extra period is not added if I redefine \theparagraph with \arabic. Also, it appears only after the second compilation of the document.

Any suggestions on how to get rid of them are much appreciated.

Answer 1

It is a KOMA Script feature to add a period after (all sectioning) numbers as soon as there is a non-Arabic number at some level. To quote the documentation (pp. 99-100 in 2021-06-25)

According to DUDEN, if only Arabic numerals are used to number section headings, the German practice is to have no point at the end (see [DUD96, R3]). On the other hand, if Roman numerals or letters appear in the numbering, then a point should appear at the end of the numbering (see [DUD96, R4]). KOMA-Script has a mechanism that tries to automate this somewhat complex rule. The result is that normally after the sectioning commands \part and \appendix the numbering switches to using a final point. This information is saved in the .aux file and takes effect on the next LaTeX run.

Sometimes the mechanism for placing or omitting the final point may fail. Sometimes other languages have different rules. Therefore you can force the use of the final point with the option numbers=endperiod or to prohibit it with numbers=noendperiod.

Note that this mechanism only takes effect on the next LaTeX run. Therefore, before you try to use these options to force the correct numbering format, you should always perform another LaTeX run without modifying the document.

If you want to stick to the Duden rules, you have to do nothing.

If you want to get rid of the period, use numbers=noendperiod.

If you want to retain the period for the paragraph heading, you can additionally redefine \paragraphformat and replace \autodot with . to force a period.

\documentclass[numbers=noendperiod]{scrartcl}

\renewcommand*{\theparagraph}{\alph{paragraph}}
\renewcommand*{\paragraphformat}{\theparagraph.\enskip}
\setcounter{secnumdepth}{4}


\begin{document}
\section{Foo}\label{sec:foo}
\ref{sec:foo}
\paragraph{Bar}\label{sec:bar}
\end{document}

Answer 2

How about using article instead of scrartcl?

%\documentclass{scrartcl}
\documentclass{article}
\renewcommand{\theparagraph}{\alph{paragraph}}
\setcounter{secnumdepth}{4}

\begin{document}
\section{Foo}\label{sec:foo}
\ref{sec:foo}
\paragraph{Bar}\label{sec:bar}
\paragraph{Barr}\label{sec:barr}

Paragraph~\ref{sec:bar} gives the proof.
Paragraph~\ref{sec:barr} gives an example.
\end{document}