> (though hardly approachable unless you already have a good handle on, say, eigenvalue decomposition, outer products = rank 1 matrices, positive semi-definiteness, etc.)

These are what are known as prerequisites. This expectation on HN that all science and math should be made approachable without requisite prior knowledge is so bizarre to me. On the other hand, if blog post is about move semantics, nobody chimes in "ha, try understanding that without knowing about constness first".