So by "graduate level", I don't mean that at no point could any undergrad follow the material. I'd wager that you're correct, most seniors, and many juniors or

So by "graduate level", I don't mean that at no point could any undergrad follow the material. I'd wager that you're correct, most seniors, and many juniors or sophomores with the right sequencing, can follow the material. But that same thing can be said about _tons_ of graduate course work. From my experience, many graduate classes have a few advanced undergrads in the class. By graduate course work, I mean "builds on an undergraduate-level understanding of the material". And yes I'm being a little hand-wavy about what demarcates grad from undergrad (which probably isn't well defined anyway), but I hope the gist of my meaning is clear.