test $\displaystyle x^-^2$
Thank you.
Another test:
$\displaystyle a = \prod {p_i}^{a_i} $
$\displaystyle \{a\} = \{{p_i}^{a_i}\} $
$\displaystyle \{ a_{odd}\} = \{p_i}^{a_i} : 2\nmid{a_i}\} $
Proposition 2) If A and B are not square and AB is square then the sets $\displaystyle \{A_{odd}\}$ and $\displaystyle \{B_{odd}\}$ are non empty and $\displaystyle \{A_{odd}\} = \{B_{odd}\}$