Too close, in my opinion. If I said "Communication is a part of physics", it would be clear that I don't mean "all of communication is a subset of physics" and

Too close, in my opinion. If I said "Communication is a part of physics", it would be clear that I don't mean "all of communication is a subset of physics" and that I do mean "doing physics involves communicating your findings". I think this is the author's intention. Edit: Actually, it does seem like the author claims mathematics is a proper subset of physics.