# Defining a command which makes a new symbol

Is there a way to define a new command which represents the function override symbol used in Event-B. There is a similar symbol \dsub that is just the triangle with the line that splits it. Thanks in advance.

• Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. – jjdb May 8 '17 at 9:58
• What is Event-B? – cfr May 8 '17 at 10:07
• @cfr Event-B is a language that uses mathematical structures to develop system models for areas such as Critical Systems – Radoslav Todorov May 8 '17 at 10:15
• – Steven B. Segletes May 8 '17 at 10:17
• My point is that your question shouldn't assume discipline-specific knowledge unless it really has to. If something is crucial, you need to explain it. The name of a symbol and context may be useful, but only as a supplement. I can't tell from your question whether the symbol you've shown is the one you need or \dsub, which seems to match the description. – cfr May 8 '17 at 10:17

## 1 Answer

At https://sourceforge.net/p/rodin-b-sharp/svn/16394/tree/trunk/Handbook/org.rodinp.handbook.feature/latex/plastex-bsymb.sty, they provide bsymb.sty and employ this definition

\documentclass{article}
\usepackage{amssymb}
\newcommand{\ovl}{\mathbin{\lhd\mkern-9mu-}}
\begin{document}\Huge
$\ovl{A}$
\end{document}


According to this site, http://wiki.event-b.org/index.php/Rodin_Keyboard_User_Guide, there is a unicode symbol U+E103 , but I haven't yet found a font that supports it (I see some web reference to one called Brave Sans Mono that might support it, but haven't found the actual font yet).

The Event-B language is discussed in great detail at http://rodin.cs.ncl.ac.uk/deliverables/D7.pdf

• @Sebastiano A little bit of sleuthing on a Monday morning. – Steven B. Segletes May 8 '17 at 10:11
• @StevenB.Segletes Do you remember this question? tex.stackexchange.com/questions/337356/…. You were the first to help me with my first question. – Sebastiano May 8 '17 at 10:21
• @Sebastiano Oh yes, that was a good question and fun to work on. This one was much more poking around on the web. – Steven B. Segletes May 8 '17 at 10:26
• @StevenB.Segletes But it had little reputation in terms of score.:-( why not do a bit of advertising? :-) – Sebastiano May 8 '17 at 10:28