I have a lemma in which I want to say something like this:
Let f be a function which satisfies either
(A) f=0 and f is continuous, or
(B) f=1 and f is well-defined.
Then f is good.
My question is, what environment should I use for the two options (A) and (B)? Should I use
description, or something else? I may say later on "If f satisfies the case (A), then ..."