Rescaling a math symbol?

Question

I am trying to rescale a math symbol while using the amsbook package. At first I was using the relsize package, but it creates clashes with the AMS packages: Amsart with algorithm2e introduces extraneous text into pdf file with Texlive 2011.

Then, I read here Change font size relative to current font size that the amsbook has a similar option. I looked it up, and there is the \larger command. But it doesn't work. I used:

  \newcommand{\Alpha}{\larger{\alpha}}

and the \alpha does not change in size.

Any ideas how to rescale the \alpha so that it is relatively larger (I used to use mathlarger from relsize which worked fine, but created clashes with AMS packages, as I said)?

Answer 1

The AMS classes have a \larger command that works out of the box:

\documentclass{amsart}
\newcommand{\Alpha}{\mbox{\larger$\alpha$}}

\begin{document}
$\alpha\Alpha$

\Large
$\alpha\Alpha$

\end{document}

This won't work in subscripts/superscripts, though. Unfortunately \text doesn't update \@currsizeindex, so using \text instead of \mbox, which would be the obvious attempt, doesn't give the desired result.

A possible way out is to update the sizes manually:

\documentclass{amsart}
%\newcommand{\Alpha}{\mbox{\larger$\alpha$}}

\newcommand{\Alpha}{\mathchoice
  {\mbox{\larger$\alpha$}}
  {\mbox{\larger$\alpha$}}
  {\mbox{\larger[-2]$\alpha$}}
  {\mbox{\larger[-4]$\alpha$}}
}

\begin{document}
$\alpha\Alpha_{\alpha\Alpha_{\alpha\Alpha}}$

\Large
$\alpha\Alpha_{\alpha\Alpha_{\alpha\Alpha}}$

\end{document}

Answer 2

You can achieve arbitrary scaling with the scalerel package. I demonstrate here with \Alpha as 1.5 times the original. (Note: in this case, \scaleobj is functionally equivalent to a \scalebox that defaults to math mode).

It also automatically obeys the current math style, as shown in the second line.

\documentclass{article}
\usepackage{scalerel}[2016/12/29]
\newcommand\Alpha{\scaleobj{1.5}{\alpha}}
\begin{document}
\( \alpha\Alpha \)

\(\Alpha^{\Alpha^{\Alpha}}\) versus
\(\alpha^{\alpha^{\alpha}}\)
\end{document}

Answer 3

with this code:

\documentclass{article}
\usepackage{scalerel}[2016/12/29]
\newcommand{\B}[2]{\scaleobj{#2}{#1}}
\begin{document}
    $\B{\alpha}{2.5}\alpha\B{\beta}{5}$
\end{document}

You have this result:

The code define a new command with 2 mandatory argument:

#1 the character to scale,

#2 the scale factor