I am writing a mathematical paper. There is a certain sequence (3) in the paper. I write:
Lemma 4.5. The sequence (3) is exact.
Is that correct, or should I better write with the zero article, like this?
Lemma 4.5. Sequence (3) is exact.
EDIT: I write a formula of a special kind, that we call "a sequence of groups and homomorphisms". This formula has a number, in my case it has number 3. After I write this formula, I claim that it has a certain property: it is "exact". The question is: should write with the definite article "The sequence (3)" or with the zero article "Sequence (3)"?