Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

Consider the following snippet:

$$\text{d}_{H}(A,B)  = \max\left\{ \sup_{a\in A} \inf_{b\in B} \text{d}(a,b),\sup_{b\in B} \inf_{a\in A}\text{d}(a,b)\right\}$$

example

In the output, the text under the inf's is significantly smaller then the one under the sup's. The same happens when I have it in an align environment.

You can see the same problem in the wiki definition of the Hausdorff distance. How can I have the typeset under the inf's and sup's in the same size?

share|improve this question
    
@Dror with a minimal using amsmath it looks the same to me, can you post a minimal? –  Yiannis Lazarides Jan 4 '11 at 6:55
2  
It is not typeset any differently. As Herbert points out, there is a height difference because inf does not descend below the baseline. You can add \let\inf\relax \DeclareMathOperator*\inf{\vphantom{p}inf} in the preamble to have them be at the same height. You can do the same for \max and \min, if you want. –  TH. Jan 4 '11 at 7:08
    
Of course, I meant to say it is not typeset at a different size. –  TH. Jan 4 '11 at 7:11
    
@Yianis: I am using amsmath and it does look odd in my case (same oddness as you can see on the wiki link). –  Dror Jan 4 '11 at 7:56
    
@TH: It's amazing how illusive it looks. Anyway, your solution worked for me. Is there a reason to keep the old \inf? Why this is the behavior for \max, \min and \inf but not for \sup? –  Dror Jan 4 '11 at 7:59

3 Answers 3

up vote 12 down vote accepted

To elaborate on @Philipp's answer: The mathtools package provides \adjustlimits, which corrects the spacing of the limits of two adjacent operators. In your example, you would use it like

\[ \adjustlimits\sup_{a\in A} \inf_{b\in B} \mathrm{d}(a,b) \]

example

Btw, if you are using LaTeX, you should use \[ ... \] instead of $$...$$ and \mathrm or \operatorname instead of \text for the d (so that it will not inherit properties (like italics) from the surrounding text).

share|improve this answer
    
As \def seems to be not recommended for regular usage, I believe this is the best solutions. Which also works for me. –  Dror Jan 4 '11 at 16:52
    
Should there be a closing \] in there somewhere? –  asmeurer Dec 8 '12 at 22:41
    
@asmeurer: yes, of course. –  Caramdir Dec 9 '12 at 16:44

it is a problem with the depth of \inf which is zero. Use it this way:

\documentclass{article}
\usepackage{amsmath}

\def\Inf{\operatornamewithlimits{inf\vphantom{p}}}

\begin{document}

\[ \text{d}_{H}(A,B)  = \max\left\{ \sup_{a\in A} \Inf_{b\in B} 
   \text{d}(a,b),\sup_{b\in B} \Inf_{a\in A}\text{d}(a,b)\right\} \]

\end{document}
share|improve this answer
    
Your solution also works, but then I have two different definitions for inf. This can cause confusions. Do you have a specific reason to keep the original \inf? –  Dror Jan 4 '11 at 8:01
    
sure, it looks ugly when I use it without a preceeding \sup –  Herbert Jan 4 '11 at 9:42
    
I see. So the whole problem is caused because of the combination of \sup and \inf and the p in the \sup, right? –  Dror Jan 4 '11 at 10:06
    
@Dror: yes, that is always a problem when having two consecutive operators with limits and not the same depth of the characters. –  Herbert Jan 4 '11 at 10:09

See section 3.1.4 of the mathtools package manual for a description and a generic solution.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.