What is permissible and not permissible when you collaborate with your fellow students on a project or assignment?

Collaboration on work done at university is often a valuable learning tool and each professor or instructor will have their own method for setting the rules for what is permitted and not permitted when there is collaboration on work done for the course.  The subject is quite complex and a few guidelines from the Academic Integrity site at Princeton University on collaboration may help you in clarifying this issue.

Remember the fundamental rule: if in doubt, ask your professor to clarify what exactly is permissible and what is not.

Collaboration and unfair advantage are often synonymous. When the assistance you provide or receive gives an advatange to one or some studens in a course, but where the advantage is not beneficial to all, it's problematic. 

For example, studying new material after class is not collaboration, but completing an assignment together that is being submitted for a grade is collaboration.