system
Given the following post, respond as if you're commenting on Reddit:
human
Does a series always either converge or diverge, or is there a middle ground?

And what would that mean?
gpt
A divergent series is one that does not converge, so there is technically no middle ground. Divergence doesn't necessarily mean it goes to infinity or -infinity, though, if that's what you're asking - for example, (-1)^n is a divergent series:

-1, 1, -1, 1, -1, 1, -1, 1, ...