4 ms·
"When I told Lichnerowicz about Leray’s suggestion, he said “it is too difficult for a beginner”. In fact it was not so difficult. In harmonic coordinates, call
by scoot 11y ago
"When I told Lichnerowicz about Leray’s suggestion, he said “it is too difficult for a beginner”. In fact it was not so difficult. In harmonic coordinates, called then “isotherm”, introduced by Lanczos, DeDonder and Georges Darmois, the Einstein equations in vacuum look like a system of quasidiagonal, quasilinear system of second order partial differential equations hyperbolic for a Lorentzian metric."
There's beginner, and then there's 'beginner'.
- WalterBright 11y ago3 years of math at Caltech, and I'm dead in the water on what that means - I don't even know the words, except that I know what second order partial differential equations are.
- kweinber 11y agoI had developed a truly marvelous explanation of that paragraph but I couldn't fit it into the margin of this page.
- theoh 11y agoIt's probably not as complicated as it is being made to sound. I don't know about the "quasis" but it sounds like a linear algebra problem. Hyperbolic might be the form of the solutions to each of the differential equations, or of their combined solution. "Lorentzian metric" presumably means the usual Minkowski space of relativity.