Designing a new mathematical operator

Question

We all know that \binom{n}{r} in math mode renders the binomial coefficient. For the purposes of a note, I am TeXing up, I am interested in designing a new math operator.

Suppose I called that operator as \bil{}{}, I would like the following input \bil{n}{r} to give <n,r>.

Can anyone please help me with how I would do that?

score 5 · Accepted Answer · answered Mar 30 '12 at 19:45

5

How about

\newcommand\bil[2]{%
  \mathord{\left<#1,#2\right>}%
}

answered Mar 30 '12 at 19:45

Stephan Lehmke

24,361

If I understand correctly, can we replace \left< by \langle. I think \langle looks good right? – kan Mar 30 '12 at 19:48
@KannappanSampath If you wish, but I believe \left< will come out as \langle. Do you see a difference (apart from the fact that \left< can grow)? – Stephan Lehmke Mar 30 '12 at 19:50
(Firstly, I agree with your code. It looks much better with \left< than with \langle.) – kan Mar 30 '12 at 20:05

score 3 · Answer 2 · answered Mar 30 '12 at 19:48

3

Someting like this will work:

\documentclass{article}

\newcommand*{\bil}[2]{\ensuremath{\langle #1,#2\rangle}}

\begin{document}

Text Text \bil{4}{11} Text Text or \bil{m}{k} even $a=\bil{u}{r}$

\end{document}

answered Mar 30 '12 at 19:48

Peter Breitfeld

3,391

Yours works just as fine. Minor Beautification: \left< and \right> works well when I tried. Thank you for the answer. +1 – kan Mar 30 '12 at 19:58
You are right, it's better, especially if you want the angle to stretch. – Peter Breitfeld Mar 30 '12 at 20:06
2

@PeterBreitfeld Please, have a look at http://tex.stackexchange.com/questions/34830/when-not-to-use-ensuremath-for-math-macro about \ensuremath. – egreg Mar 30 '12 at 21:31
@egreg, thank you for this interesting link. – Peter Breitfeld Mar 30 '12 at 21:49
3

The "use-\ensuremath-only-when-really-needed" campaign is still going on. :) – egreg Mar 30 '12 at 21:55

Designing a new mathematical operator

2 Answers2