> The raw mathematics isn't the hardest; most of this is settled by the end of the second year of undergraduate physics—things like Taylor series, ODEs, PDEs, special functions, a bit of linear algebra (no proofs needed, just use the results); perhaps complex analysis which leads to Fourier transforms and all. Maybe a treatment of tensors.

It sounds like the OP is saying you could tackle the article if you just know a little high school calculus and trig, and you're here saying that you need years of post-secondary mathematical education. I think you're making his case that he's dramatically simplified understanding how to compute these things for someone who doesn't have a post-secondary education.