titlesec error "undefined control sequence"

Question

I'm new to titlesec and LaTeX in general, trying to use it to achieve chapters in a {book} class that are medium-sized and on the same line, viz:

Chapter 1: An Unlikely Event

Here's a minimized example:

\documentclass[english,12pt,oneside]{book}
\usepackage{titlesec}
\titleformat{\chapter}[hang]{\normalfont\medium\bfseries}{\chaptertitlename\ \thechapter:}{1em}{}
\begin{document}

\chapter{An Unlikely Event}

\end{document}

The error that returns is:

ERROR: Undefined control sequence.

--- TeX said ---
<argument> \normalfont \medium 
                               \bfseries 
l.77 \chapter{An Unlikely Event}

--- HELP ---
TeX encountered an unknown command name. You probably misspelled the
name ...

I think this is probably a simple error on my part, but I'm too young to know what it is.

since you're specifying fonts, and the next thing you ask for is \bfseries, you needn't specify "medium". there is \mdseries, to which is equated \mediumseries, but no \medium -- but since it's redundant anyhow, you can just get rid of it. — barbara beeton, May 26 '15 at 19:35
\medium is a command that doesn't exist. Probably you meant mdseries. — Bernard, May 26 '15 at 19:37
I was trying to specify the size of the font, but I must have misunderstood the advice here: http://tex.stackexchange.com/questions/59726/change-size-of-section-subsection-subsubsection-paragraph-and-subparagraph-ti — Steven Arntson, May 26 '15 at 19:45
@StevenArntson -- then what you probably meant was \normalsize. — barbara beeton, May 26 '15 at 19:53
My solution is to do medium in this way: \usepackage[medium]{titlesec}. This seems to work. Thank you, -s — Steven Arntson, May 26 '15 at 20:00
Yes, \normalsize works just the same---I will use that. Thank you! -s — Steven Arntson, May 26 '15 at 20:02
titlesec documentation is a bit misleading as it lists big medium small tiny as valid format parameters. After more attentive reading, they appear to be format options for the package, not for the \titleformat command. — Akseli Palén, Jun 13 '15 at 22:34

score 1 · Accepted Answer · answered Jul 04 '15 at 22:13

1

you have used the command \medium, which doesn't exist. what you probably meant is \mdseries, which is the default.

since you responded in a comment that what you really want to do is change the size of the font, the command for that is \normalsize.

answered Jul 04 '15 at 22:13

barbara beeton

88,848

titlesec error "undefined control sequence"

1 Answers1