Generalized Laplace transformations and integration of hyperbolic systems of linear partial differential equations
Sergey P. Tsarev
TL;DR
The paper addresses factorization and complete integration of strictly hyperbolic LPDEs in the plane by generalizing Laplace factorization to $n\times n$ hyperbolic systems. It develops a recurrent framework based on converting to characteristic form, defining Laplace invariants, and applying multi-step transformations that progressively simplify the system toward (block-) triangularity and solvability. The approach yields closed-form solutions in many cases without solving auxiliary differential equations and is applicable over arbitrary differential fields. A concrete $3\times3$ example demonstrates the method and outlines a practical scheme for generalized factorization and integration of higher-order hyperbolic PDE systems.
Abstract
We give a new procedure for generalized factorization and construction of the complete solution of strictly hyperbolic linear partial differential equations or strictly hyperbolic systems of such equations in the plane. This procedure generalizes the classical theory of Laplace transformations of second-order equations in the plane.
