In an unrelated reply to one of my questions, someone used the following expression type.
x and y are on par while x and z are not
I use a similar expression (see below). However, I'm curious if they are equivalent with respect to colloquial meaning, popularity, etc. In fact, I'm a bit worried that the one I am used to is incorrect (or maybe archaic or confusing).
x and y are in parity, while...
or
x and y are of the same parity, while...
Are both ways on par with each other or are they of different parity (yes, the usage of both is intended)? In what why do they differ?