I am correcting a journal paper about mathematics.
Is this a correct and complete sentence:
The latter is a leaf and the former a branch.
(I did not provide the context of the sentence, since I don't think it is necessary for the grammar. My co-author had a comma before the word "and", which is definitely wrong in my opinion. I goggled "conjunctive clause" but did not find a helpful answer. Btw, my mother tang is German.)
Btw, I was looking for an explanation such as given by G.L. "The gapping rule".