On another site it sometimes happens that I give answers like:
The first formula is correct but not the second one.
This is probably grammatical, but I find the formulation a bit clumsy, perhaps because of the influence of other languages I am familiar with, where the pronoun one is not used.
So my question is whether a formulation like
The first formula is correct but not the second .
or some other variant exists, which would be perceived as more elegant but still natural by a native speaker of English.