Let's say I don't like the way the + symbol is printed inside equation: is there a way to change its appearance without defining a new command?
More generally, is it possible to create a command without the initial backslash?
[Tex/LaTex] How to redefine the “plus” symbol
equationsmacrossymbols
Related Solutions
You could create your own symbol using ooalign
as demonstrated in
- What is the command for a sum symbol superimposed on an integral sign?
- \subseteq + \circ as a single symbol ("open subset") which contains a great tutorial on
ooalign
The subtle thing in the code below is that I've used a \phantom{sum} in the displaystyle version to make sure that limits of the sum are displayed correctly. Without it, you loose the correct display of the upper limit.
If the circles aren't exactly where you want them, you can move them around by playing with the numbers in the code.
\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}
% a new command to draw the little circle
\newcommand{\smallcirc}[1]{\scalebox{#1}{$\circ$}}
\DeclareMathOperator*{\SumCircles}{%
\mathchoice%
{\ooalign{\phantom{$\displaystyle\sum$}\cr\hidewidth\raisebox{1.2\height}{$\mkern22mu\smallcirc{0.7}$}\hidewidth\cr%
\raisebox{-0.7\height}{$\mkern22mu\smallcirc{0.7}$}\cr
\hidewidth$\displaystyle\sum$}}
{\ooalign{$\textstyle\sum$\cr%
\hidewidth\raisebox{1.9\height}{$\mkern16mu\smallcirc{0.4}$}\hidewidth\cr
\hidewidth\raisebox{-.3\height}{$\mkern16mu\smallcirc{0.4}$}\hidewidth\cr}}
{\ooalign{\raisebox{0\height}{\scalebox{.6}{$\scriptstyle\sum$}}\cr%
\hidewidth\raisebox{1.6\height}{$\mkern7.5mu\smallcirc{0.2}$}\hidewidth\cr
\hidewidth\raisebox{-0.2\height}{$\mkern7.5mu\smallcirc{0.2}$}\hidewidth\cr}}
{\ooalign{\raisebox{.2\height}{\scalebox{.6}{$\scriptstyle\sum$}}\cr%
\hidewidth\raisebox{2.2\height}{$\mkern7.5mu\smallcirc{0.2}$}\hidewidth\cr
\hidewidth\raisebox{0.4\height}{$\mkern7.5mu\smallcirc{0.2}$}\hidewidth\cr}}
}
\begin{document}
$\SumCircles_{\SumCircles} \displaystyle\SumCircles$
\[
\SumCircles_{n=1}^\infty
\sum_{n=1}^\infty
\]
\end{document}
Scott Pakin's Comprehensive LaTeX Symbol List identifies the structure of extensible delimiters in section 8.2 Resizing symbols (p 100-102):
All variable-sized delimiters are defined (by the corresponding
.tfmfile) in terms of up to five segments, as illustrated by Figure 1 on page 102. The top, middle, and bottom segments are of a fixed size. The top-middle and middle-bottom segments (which are constrained to be the same character) are repeated as many times as necessary to achieve the desired height.
This is merely informative since I am unfamiliar with the procedure of how to create these things in a .tfm file.
Conveniently, scalerel provides \scaleleftright[<max width>]{<left obj>}{<stuff>}{<right obj>} (and a comparable \stretchleftright) for scaling/stretching both <left obj> and <right obj> to the height of <stuff> (constrained, if required and optional, to a width of <max width>). Here's a quick example:
\documentclass{article}
\usepackage{scalerel}% http://ctan.org/pkg/scalerel
\begin{document}
\[ \stretchleftright{\dagger}{\displaystyle\sum_{i=1}^n i}{\dagger} \]
\[ \scaleleftright{\dagger}{\displaystyle\sum_{i=1}^n i}{\dagger} \]
\end{document}
Best Answer
Yes, of course.
Of course you can think to better definition for the “math active”
+.;-)A more general approach where you can also use an equivalent of the character being “redefined”.
In the optional argument to
\mathactivedefyou set the equivalent name that you can use in the body of the redefinition.The previous “blurb” (without keeping the meaning of
+) would be