It shouldn't be necessary to mention this in a graduate-level seminar, but the issue has come up in the past so I feel that I should state my policies clearly up front.
Dishonest behaviors, including but not limited to plagiarism, copying of another student's work (or providing your own to another), group consultation on individual projects or work, etc., will not be tolerated. My general feeling is that being caught cheating should be more painful than not having done the assignment at all. Therefore, I will generally at least assign a negative penalty equal to the full value of the assignment if I discover someone cheating on an assignment. I.e., if an assignment is worth 10% of the final grade, the individual would receive not zero credit for the assignment, but -10%. And, of course, if you're clever enough not to get caught, then you're clever enough not to need to cheat in the first place.
That said, this is a graduate pre-research seminar and I do want to encourage collaborative thinking and discussion. Therefore, I encourage you to discuss a number of the class assignments. Specifically:
Most importantly, if you have a question about whether some specific collaboration is permissible, please ask me before you do it.