I do not officially study mathematics, so I always rely on what's on the internet. Specifically, I follow the schedules of the Tripos – the math program at Cambridge, supposedly one of the most demanding, very well-known math programs.
There was one thing that bothered me about the schedules:
Why is combinatorics not a part of the Tripos?
As far as I can see, graph theory is the only combinatorics subject in there, but it comes much later, in Part 2.
Feel free to remove this post if it's too irrelevant.