# Constructing general ligatures

I know that LaTeX has macros \ae, \oe etc. for the standard ligatures (i.e. æ, œ).

Is there a more general way to construct ligatures in the equation environment?

I'm working in the language of higher types, with function variables f,g,h,.. and I want to denote sequences of functions as ligatures fs,gs,hs,... This avoids ugly vector/bold notation.

• TeX does not construct ae it is a distinct glyph in the font. How close do yo do you want fs TeX does not add any space between $fs$ $\mathit{fs}$ usually gives closer spacing as it is a text font or $f\mkern-1mu s$ or .... – David Carlisle Feb 27 '13 at 18:57
• If I could define a macro that returns fs in equation environment so that they are touching as with \ae that would be great. \mathit{fs} still leaves a small gap. – Tom Feb 27 '13 at 19:02
• Welcome to TeX.sx! We usually do not add thanks, instead simply upvote any good answers you may receive. – Peter Jansson Feb 27 '13 at 19:08
• Would a negative space, e.g. \! or \hspace{-0.2em} or whatsoever, be helpful? – Stephen Feb 27 '13 at 19:52
• It is also not clear from your question whether when you use the word "ligatures" whether you mean something typographic (kerning) or shorthand notation (\def) to refer to longer sequences of math characters strung together. The latter would be a very simple solution indeed. – Steven B. Segletes Mar 6 '13 at 15:15

I think you are looking for kerning (inter-letter space added by the typesetting engine) rather than ligatures (a pre-built glyph in the font).

This moves f and s as close as I dare:

\documentclass{article}
\begin{document}

$\mathit{fs}$

$\mathit{f\mkern-6mu s}$

\end{document}