# \left \right for the bracket of a function

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?

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• \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}


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I believe there exists a \tfrac in amsmath ;) –  yo' Nov 15 '12 at 9:45

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.

## 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}

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how about the space between Y and ()? –  hyh Nov 15 '12 at 7:32
Updated example to show how to reduce the space between the Y and (. –  Peter Grill Nov 15 '12 at 7:37
@PeterGrill -- when the Y is scaled, its height increases (as intended), but now it looks very unbalanced with respect to the math axis (the relative height of the fraction bar). maybe this looks better in a more elaborate context, but alone it looks like it is trying to be a "large operator" (like a sum), and fails miserably. without knowing the intent of this request, my immediate reaction is that it is misguided. –  barbara beeton Nov 15 '12 at 13:48
@barbarabeeton: Totally agree. Did not intend to be advocating enlarging the text, just providing a way to do what the OP desired. I have updated to apply a \raisebox to shift the scaled Y down slightly. –  Peter Grill Nov 15 '12 at 20:06

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.

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