One possibility: I used \DeclarePairedDelimiterX
from the mathtools
package to define a \MeijerM
command with three arguments which is responsible to typeset the delimited matrix; then I defined \MeijerG
having eight arguments (the first one is optional and will be passed as the optional argument to \MeijerM
); using the \WithSuffix
command from the suffix
package to provide the starred version \MeijerG*
:
\documentclass[11pt]{article}
\usepackage{suffix}
\usepackage{mathtools}
\DeclarePairedDelimiterX\MeijerM[3]{\lparen}{\rparen}%
{\begin{smallmatrix}#1 \\ #2\end{smallmatrix}\delimsize\vert\,#3}
\newcommand\MeijerG[8][]{%
G^{\,#2,#3}_{#4,#5}\MeijerM[#1]{#6}{#7}{#8}}
\WithSuffix\newcommand\MeijerG*[7]{%
G^{\,#1,#2}_{#3,#4}\MeijerM*{#5}{#6}{#7}}
\begin{document}
\[
\MeijerG*{m}{n}{p}{q}{a_1, \dots, a_p}{b_1, \dots, b_q}{z}\quad
\MeijerG[\big]{m}{n}{p}{q}{a_1, \dots, a_p}{b_1, \dots, b_q}{z}\quad
\MeijerG[\Bigg]{m}{n}{p}{q}{a_1, \dots, a_p}{b_1, \dots, b_q}{z}
\]
\end{document}
The size of delimiters in the second and third examples is obviously wrong, but I just included them to test the functionality of the defined commands. Also, I used simple sub/superscripts to typeset the first four arguments, but of course you can use one of your proposed variants instead.
Semantically, don't use either. Use \conj
, or \mean
, or \variant
or whatever the overline is meant to mean. Then in your preamble, do:
\newcommand*\conj[1]{\bar{#1}}
\newcommand*\mean[1]{\bar{#1}}
Then:
- Your document source becomes readable: you can determine the meaning right there and then.
- Your document becomes more flexible: if you decide to denote complex conjugation by a star instead you can simply redefine
\conj
without worrying about changing what \mean
does.
- You can change from
\bar
to \overline
on a whim and don't have to make that crucial decision now.
Best Answer
This seems a matter of preference to me. I personally always prefer to use
\overline
, as I find the\bar
line to be very short (particularly if you have something wider than a single letter, likef_T
). Apart from that preference, I'd point out two small differences between including the_T
under the line, or not.f_T
, you mean: the mean off
, and afterwards specifying someT
, I would suggest\overline{f}_T
f_T
is the actual function you are taking a mean of, I would suggest\overline{f_T}
By your description, I would suggest the second.
In general, if you are unsure, you can always make a command
and use
\mean{f_T}
, so you can change to\bar
if you'd prefer that at a later point.