Question is who holds the copyright over the lecture notes? The notetaker, or the lecturer? Or both?
In most cases, probably the university. They generally claim copyright on everything anyone does within 100 miles of the uni.
I don't think it matters though - the mathematics isn't copyrightable, just the way it's written in the notes, and I don't think anyone is planning on just typing up the notes, they're talking about using them as sources for an article.