# My prime symbol is not superscript

I'm learning math mode and having an issue here with the prime symbol.

$y\in[0,1]^{d\prime}$


In this inline math formula, the prime symbol is supposed to be superscript, but it shows up at the regular text level and size.

It is not clear what you want the output to be

$y\in[0,1]^{d\prime}$


the \prime is in the superscript along with d. If you want the prime to be on d then just use

$y\in[0,1]^{d'}$


which is equivalent to

$y\in[0,1]^{d^{\prime}}$

• Thank you. I needed the extra explanation as well as the answer. I'm not up to speed on this language. Commented Feb 3, 2013 at 0:54
• +1 for noting apostrophe (') is, in math mode, the same as ^{\prime} Commented Feb 3, 2013 at 16:11
• @AlexNelson, I think that that's only approximately true. Namely, $$d'$$ is the same (I guess) as $$d^\prime$$, but $$d''$$ is not the same as $$d^\prime^\prime$$. (I think ' does some \ifnextchar monkeying precisely to handle this.) Commented Jun 17, 2015 at 20:01
• @LSpice \futurelet rather than \@ifnextchar but yes. Commented Jun 17, 2015 at 20:05

\prime is by default on the same level as normal text. (Just as \circ - used as symbol for degrees for example.) Instead you need to specify that \prime is a superscript:

$y\in[0,1]^{d^\prime}$


EDIT: This might be marginal to the question, but I think it's a useful addition. The ' is a shorthand for ^\prime. Thus, if you type in LaTeX:

$y\in[0,1]^{d^{\circ'}}$


the output will be:

As you can see, LaTeX interprets it as a double superscript. Now suppose you don't want that, but instead something like:

If you try to do it by typing: $y\in[0,1]^{d^{\circ}'}$, you'll summon up an error:

! Double superscript.
l.4 $y\in[0,1]^{d^{\circ}'  To avoid this, \prime comes handy. Just do: $y\in[0,1]^{d^{\circ\prime}}\$ and everything will be fine. :)
• Duplicated from tex.stackexchange.com/questions/96558/…: I think that "The ' is a shorthand for ^\prime." is only approximately true. Namely, $$d'$$ is the same (I guess) as $$d^\prime$$, but $$d''$$ is not the same as $$d^\prime^\prime$$. (I think ' does some \ifnextchar monkeying precisely to handle this.) Commented Jun 17, 2015 at 20:04