# How to make the function identifier ( f(x) ) more dominant?

When a function has a rather complex set of parameters, the function identifier (usually simply f), gets dwarfed by the parentheses and the parameters inside of them: As you can see in the red circle, the "f" looks more like a factor, than the function name. The way how the function is displayed in the blue circle is fine. I used the same code, basically, for both function names (simplified code):

$$f\left(\xi_{n,j}\right)$$


and

$$f(x)$$


Now, is there a way how to make the function identifier more "prominent", so it does not look like a factor to a parenthesis, but something more important I guess?

• There's no need to grow the size of the parentheses in the case at hand: f(\xi_{n,j})(x_{n,j}-x_{n,j-1}) is just what's needed. – egreg May 3 '12 at 14:05
• @egreg yeah, but the idea is, to grow the size of "f". It's a function identifier, and to my understanding, that one should always be at the same size as the paramteres. my idea was simply to somehow increase the font size for the "f" or something. – polemon May 4 '12 at 16:38

I think this is due to \left( adding some horizontal space. Compare with:

$f\left(x^2 \right)$
$f\Bigl(x^2\Bigr)$
$f(x)$

• In general, \left and \right should imho be avoided whenever possible. – mbork May 3 '12 at 14:02
• @mbork I think so too. But sometimes e.g. for very high formulas extending the height of \Bigg you'll need it. – Peter Breitfeld May 3 '12 at 14:04
• Increasing the size of f or something in the likes isn't a good idea? – polemon May 3 '12 at 14:28
• @mbork IMHO, \left and \right should be re-coded so that they do not produce this stupid spacing. – yo' May 3 '12 at 14:34
• I read through the article that Michel Fioc linked. It actually helps a lot! – polemon May 3 '12 at 16:16

This problem has been discussed in Spacing around \left and \right. To solve it, you may use the mleftright package of Heiko Oberdiek.

• I just added the four lines that were advised there to my preamble. It seems to work OK. – polemon May 4 '12 at 16:37