# Math-Mode: No-Delimiter

This is a subquestion related to Evaluation Symbol.

Is there something of the form \left<?> instead of \left. telling LaTeX to enclose the expression here and not to insert any delimiter at all, no matter wether visible or invisible?

As an example I want:

\left<no-delimiter><stuff>\right|_<index>

• Can you clarify your question, I can not guess what input or output you intend. If you do not want any delimiter why do you need any markup at all? – David Carlisle Dec 11 '14 at 9:55
• Of course, a moment, please. – C-Star-W-Star Dec 11 '14 at 9:57
• looking at the referenced question it seems that you want \left. but after setting \nulldelimiterspace=0pt Is that a correct interpretation of your question? – David Carlisle Dec 11 '14 at 9:57
• YES!! But doesn't . stand for spacing. Does there exist \nulldelimiter? – C-Star-W-Star Dec 11 '14 at 10:02
• \newcommand\noleft{\left.\kern-\nulldelimiterspace} – egreg Dec 11 '14 at 10:02

When \left. is used, TeX inserts no delimiter, but adds a space of width \nulldelimiterspace. It's not advisable to set this parameter to zero, in my opinion. But with

\newcommand{\noleft}{\left.\kern-\nulldelimiterspace}

using

\noleft x\right|_{a}

will in any case remove the added space.

As explained in my answer to the referenced question, using a macro would be much better for ensuring consistency. If your aim is to get code that works also with MathJax out of the box, you're on the wrong road: the capabilities of MathJax are limited and so you are forcing yourself into using bad LaTeX.

• Great!! Thanks alot!! :) Btw what does \kern do precisely? – C-Star-W-Star Dec 11 '14 at 10:18
• @Freeze_S It inserts another space, which is the negative of the kern inserted by the null delimiter. – egreg Dec 11 '14 at 10:46
<stuff>\big|_<index>

is also possible. There is also \Big, \bigg, and \Bigg

\usepackage{mleftright}
\[ x \mleft. \frac{1}{2} \mright|_i ]|

The package mleftright fixes the spacing of \left. and \right|, so that it is the same as in $x \frac{1}{2} |_x$ but the | vertically stretches as you were using \left. and \right|.

So \mleft. should do what you do (null delimiter, no space), but consider that the space after \mright| is reduced too.