grammaticality - Is this a correct sentence: The latter is a leaf and the former a branch

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".

Answer

The latter is a leaf and the former a branch.
Looks fine enough. Why not speak in chronological order and say "The former is a branch and the latter a leaf."