Two names, forever joined by a hyphen. Jørgen Pedersen Gram (1850–1916) was a Danish mathematician who spent most of his career in the insurance business, doing deep maths on the side. Erhard Schmidt (1876–1959) was a German mathematician, a student of the legendary David Hilbert, and a founder of the modern theory of infinite-dimensional spaces. They never worked together — but their names are now inseparable.
Give a computer a jumbled set of vectors and it will almost always want them
orthonormal — all at right angles, all length one. The recipe that straightens
them out, one vector at a time, subtracting off the parts that already point the wrong way,
is
Gram's name also lives on in the Gram matrix and the Gram determinant, while Schmidt's turns up in the Hilbert–Schmidt operators that power quantum mechanics and functional analysis.
The delicious irony: the "Gram–Schmidt" process was arguably used by Laplace and Cauchy long before either man was born — Gram and Schmidt just wrote it up cleanly around 1900, and the name stuck. And Gram's own end was pure bad luck: this careful, methodical actuary who spent a lifetime calculating risks was killed in 1916 when he was struck by a bicycle on his way to a meeting. Even mathematicians can't compute their way out of everything.