# How do I change the subsection by Roman letter to number in Lyx?

I am using one IEEE template to write one two column paper, after converted into pdf format, the subsection is identified with Roman letters, such as I, II, III, IV, etc. I want to change it to numbers like: 1, 2, 3, 4, etc.

How can I do that?

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Does adding the command \renewcommand{\thesubsection}{\thesection.\arabic{subsection}} to your document preamble solve this problem? –  Werner Oct 16 '11 at 18:50
In Lyx you can access the preamble from menu: Document > Document Settings > LaTeX Preamble. –  Alexey Romanov Oct 16 '11 at 18:55
it still shows Roman letters –  Mike Oct 16 '11 at 19:24
@Mike: Please add a minimal working example (MWE) that illustrates your problem. Remember, keep it minimal, so just include your \documentclass, the required packages, and some sectional headings, so we can see your Roman subsection letters. –  Werner Oct 21 '11 at 3:55

Indeed, the IEEEtran class defaults to upper case Roman numerals for sections and upper case letters for subsections, and adding \renewcommand{\thesubsection}{\thesection.\arabic{subsection}} seems to have no effect.

However, there is a [compsoc] class option that is intended to mimic the format of the IEEE Computer Society's publications, and one those adjustments that is made with this is that Arabic numerals are used exclusively for sections and subsections. So the following MWE produces the desired results:

\documentclass[compsoc]{IEEEtran}
\begin{document}
\section{Section One}
\subsection{First Subsection}
\end{document}


There are other things that this option effects so is best to refer to the package documentation.

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The IEEEtran class numbers sections with Roman numbers and subsections with letters.

So the correct remedy is

\renewcommand{\thesection}{\arabic{section}}

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This seems to work for \section but not \subsection as per the OP. –  Peter Grill Oct 28 '11 at 22:24
@PeterGrill The subsections are not numbered with Roman numbers as the OP says. –  egreg Oct 28 '11 at 22:27

Looking through the IEEEtrans.cls file, you'll see that they use:

\def\thesectiondis{\thesection.} % I.

\def\thesubsectiondis{\Alph{subsection}.} % B. \def\thesubsubsectiondis{\arabic{subsubsection})} % 3) \def\theparagraphdis{\alph{paragraph})} % d)

for non comsoc papers. To change the section numbering simply redefine the above four lines according to you requirements. For example, if you want full arabic separated by full stops (as is the case for comsoc) then use:

\def\thesectiondis{\thesection.} \def\thesubsectiondis{\thesectiondis\arabic{subsection}.} \def\thesubsubsectiondis{\thesubsectiondis\arabic{subsubsection}.} \def\theparagraphdis{\thesubsubsectiondis\arabic{paragraph}.}

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I just realised that this has already been answered here. –  jsaven Dec 8 '13 at 2:26