[williamstein]

I strongly agree with you. When I was an undergraduate long ago, I remember getting lectured at great length by a math professor who was angry that many of the students in his abstract algebra course had worked together on the homework. I was one of those students (who had worked together), and I was very puzzled and annoyed by the professor, since I knew that I had learned far more on that assignment than any other! As a result -- I'm a college professor (in computational math), and over the last fifteen years on EVERY homework assignment I've given, I've explicitly encouraged students to work together as long as they clearly acknowledge who they worked with (and how). I wish everybody else did the same.