\left \right for the bracket of a function

Question

I'm writing something like a function Y(-), where the term in the bracket is large, so I wrote Y\left(-\right), however, the "Y" is still the normal size, which makes it looks small, compare with the \left( next to it. And the space between the two is large. Anybody can help me with this?

Answer 1

• \mleft and \mright of package mleftright avoid the additional spacing of \left and \right.

• I would not increase the size of Y. It looks odd, if it is then be combined with unscaled versions. Also scaling increases the boldness of the glyph.

  The arguemnt can be decreased with a smaller math style depending on its contents. In case of a fraction \textstyle helps, if the fraction is in a displayed equation (\displaystyle).

Example file:

\documentclass{article}
\usepackage{mleftright}
\begin{document}
\[ Y\left(\frac{1}{2}\right) \]
\[ Y\mleft(\textstyle\frac{1}{2}\mright) \]
\end{document}

Answer 2

You could load the relsize package and use its command \mathlarger on the symbol Y, i.e., \mathlarger{Y}. Continue to use \left and \right on the parentheses.

Answer 3

The \left, \right construct is intended to scale the braces, not the preceding text. However, you can use something like \scalebox to scale the preceding text, and apply a \kern to shift the paren to the left. To make sure that the Y is aligned I use \raisebox to move it down slighlty (adjust the parameters to suit).

Here is a normal usage, \scalebox applied to the Y and, a \scalebox followed by a \kern:

Notes:

• As Heiko Oberdiek, and Barbara Beeton have pointed out scaling one character in such a context is usually not really a good idea, so use with care.

References:

• How to make math font huge

Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}

\newcommand*{\LargeY}{\raisebox{-0.40ex}{\scalebox{1.5}{$Y$}}}%

\begin{document}\noindent
\[
    Y\left(\frac{1}{2}\right)
    \quad\LargeY\left(\frac{1}{2}\right)
    \quad\LargeY\kern-0.4em\left(\frac{1}{2}\right)
\]
\end{document}