[bobby358]

I learned the spectral theorem with a couple applications in the first semester of my electrical engineering graduate studies. First year graduate material is commonly called basics in my experience. Compared to the state of the art, it is. Compared to what an undergraduate freshman knows, not so much.

[nostrebored]

Right, it's material I covered in my senior year of undergrad taking hpc grad courses. If it were covered anywhere in the second semester of undergrad I would be shocked.