---
title: "Kurt Otto Friedrichs"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "Kurt Otto Friedrichs"
aliases: []
first_seen: "2026-10-30T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["symmetric hyperbolic systems","well-posed initial-value problems","partial differential equations","general relativity (mathematical foundations)"]
seek_code_commit: "d40ee39"
---


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 [[entity-james-owen-weatherall|Weatherall]] and Eleanor March's 2026 paper generalizes to the "natural equation" setting of general-relativistic field theories.

## References
- [[claim-march-weatherall-causal-cones-coincide-with-metric-lightcones]]