I have ran into really funny trouble trying to use \overset and \mathbb the same time. I need to do something like this:

enter image description here

but with the T as mathbb, i.e. \mathbb{\overset{m}T}_{ij}. When I try it, this happens:

enter image description here

  • Why?
  • How can I make it work?

Note: Putting \overset before the mathbb doesn't work.

2 Answers 2


You need to put the T inside the overset:


enter image description here

  • Done. The answer was posted so immediately I couldn't do that cause of 10 mins non-optional delay. Dec 2, 2015 at 15:07

While the accepted answer provides the solution, I wish to address the "Why?" issue in the question.

The \mathbb alphabet is defined by amsfonts.sty as


which basically means "use the glyphs from the font AMSb" (which is also declared by amsfonts). The font AMSb contains the blackboard-bold capital letters and a whole bunch of other symbols. So when you type \mathbb{T} you obtain what you expect; but \mathbb{m} looks for the glyph in the slot "6D, which is not a small blackboard-bold m (it doesn't even exist in AMSb) but rather the symbol \gtrdot, thus explaining the weird result.

  • Thank you very much, I really appreciate that someone picks the "Why" part as well! Dec 2, 2015 at 16:49
  • Incidentally, is there a package that provides blackboard-bold lowercase (or even Greek) letters which are consistent with the AMS style? The ones I've seen don't match up very closely. Dec 2, 2015 at 21:26

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