How do I place a underbrace in a subscript?


does not typeset correctly (the 3's are not subscript sized)


2 Answers 2


How about a quick and simple I_{2,(\underbrace{\scriptstyle3,3,3,3,3}_5)}?


Jan already gave a good answer. However, I'd say it's a real weakness of \underbrace that you have to do this manually. (One might even call it a bug.) Here's a surprisingly complicated redefinition of \underbrace that automatically inserts \scriptstyle if needed.


One of the problems I had to overcome is very similar to this question of mine: The underscore must go inside the mathpalette (if present).

  • 1
    I'll add something like this to unicode-math when I tackle the other under/over brace issues. Thanks! Nov 16, 2010 at 14:04
  • @will: luatex seems not to have a problem here, the digits are in script style already with no other modifications (it seems an issue confined to the plain tex definition of underbrace) Nov 16, 2010 at 15:13
  • @Khaled yeah, I was more referring to the terrible brokenness of these in xetex. Nov 16, 2010 at 15:18

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