# Spacing in a multi-lettered subscript word is too large [duplicate]

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:

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

## marked as duplicate by David Carlisle math-mode StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Feb 9 '17 at 22:06

• 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
• 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.