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I'm a new user of Latex and still trying to figure it out. Currently I have a problem where if I want to have a subscript which contains more than one letter, the spacing between the letters is too large. Namely, writing $\hat{\tau}_{eff}$ results in:

effective time constant estimate

What would be the best way to bring "eff" closer together?

marked as duplicate by David Carlisle math-mode Feb 9 '17 at 22:06

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  • I think, eff should be in text mode, not in math mode, so \hat{\tau}_{\text{eff}} (requires amsmath or mathtools package ) – user31729 Feb 9 '17 at 21:49
  • It definitely helps, but then I loose the nice italic effect. I can add it though with $\hat{\tau}_{\text{\textit{eff}}}$. Do you know what is the best practice when it comes to subscripts? – MarkoF Feb 9 '17 at 21:52
  • Use \mathit{eff} instead – user31729 Feb 9 '17 at 21:55
  • _{\textit{eff}} is enough. However, I would not recommend it, as it is a bit confusional with italic variables in formulae. – Bernard Feb 9 '17 at 21:55
  • 1
    The whole point of the design of the default math italic font is to make adjacent letters clearly not parts of a word, but look like a product of variables. \mathit is the test italic font, for use in math mode, which is designed for words. – David Carlisle Feb 9 '17 at 21:58

Christian Hupfer and David Carlisle pointed out that _{\mathit{eff}} command is the correct answer. It solves both the kerning issue and keep the word in italic.

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