On some other exercises, I get a wrong answer for not including the particle は after 来週. Why is it okay to omit here? Is it just less formal to omit it? If so, it should be an accepted answer elsewhere.
I was specifically marked wrong for including the は particle (as in, 来週はかれに会います) -is there a specific reason it should not be used? Perhaps something to do with the fact that 会います requires an obligatory に particle and the は particle confuses the sentence?