Kurt Otto Friedrichs

Mathematician whose 1954 paper, "Symmetric hyperbolic linear differential equations" (Communications on Pure and Applied Mathematics 7, 345–392), established the classical existence-and-uniqueness theory for symmetric hyperbolic systems — the standard framework for well-posed initial-value problems in field theories, including the finite propagation speed bounded by the system's characteristic cones.

Matters to this vault as the originator of the theory Weatherall and Eleanor March's 2026 paper generalizes to the "natural equation" setting of general-relativistic field theories.

References

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