In math mode, writing \prime gives too big a "prime" symbol, and it isn't a superscript, like it always is in textbooks. Why is this?
This isn't a question about how to get \prime to be a superscript, I know that. The questions is about the reasoning behind why it isn't like that by default.
This is actually one of the exercises in The TeXBook :) (exercise 16.5, p. 130):
Why do you think TeX treats
\primeas a large symbol that appears only in superscripts, instead of making it a smaller symbol that has already been shifted up into the superscript position?
And the answer is:
The second alternative doesn’t work properly when there’s a subscript at the same time as a prime. Furthermore, some mathematicians use
\primealso in the subscript position; they write, for example,$F'(w,z)=\partial F(w,z)/\partial z$and$F_\prime(w,z)=\partial F(w,z)/\partial w$.
\prime the same way is natural in the sense that it fits with the rest of the system.
– خالد حسني
Sep 01 '10 at 13:06
\prime macro existed so that one can write expressions such as f^{\prime,n}. After reading your answer I realized that f'^n works fine.
– Aditya
Oct 01 '11 at 02:15
There are situations where you need the big \prime instead of small '
e.g. $J^{v\prime h}$ looks great, but $J^{v ' h}$ wont serve as good as the previous one.
If the default is subscript, that would appear to make the regular form inaccessible, essentially removing functionality.
edit: this appears to mesh with a statement on wikipedia which suggests the prime symbol is big so that it can be optionally subscripted.
'produces a superscript “prime”. Maybe\primeis just the command that holds the symbol, and it's only intended to use for defining other commands (such as')? – Juan A. Navarro Sep 01 '10 at 11:07