"I'll be back in a week" means "I'll be back after a week has passed" or "I'll be back after the next seven day's period is over".
I was very much wondering if "I'll be back after a week" is also valid. I've done a ton of research only to fail to come up with any answers.
If it is, does the "after a week" version mean just about the same thing as the "in a week" version? Are they, I mean, interchangeable?
Or does the "after a week" version have a slightly different meaning, like "I'll only be back after a week has passed" or "I won't be back until a week has passed"?
Or is it just that few English speakers have chosen to use it irregardless of its being perfectly grammatical as well as logical?