Gordienko, V. M. Hyperbolic systems equivalent to the wave equation. (Russian, English) Zbl 1224.35245 Sib. Mat. Zh. 50, No. 1, 19-27 (2009); translation in Sib. Math. J. 50, No. 1, 14-21 (2009). Summary: Some relation along an additional characteristic is constructed for a class of Friedrichs hyperbolic systems to which the wave equation is reduced. The statement is proven about preservation of a vortex. The conditions are stated for the solutions to Friedrichs hyperbolic systems of this class to remain solutions to the initial wave equation. Cited in 4 Documents MSC: 35L05 Wave equation 35L40 First-order hyperbolic systems Keywords:wave equation; Friedrichs hyperbolic system PDFBibTeX XMLCite \textit{V. M. Gordienko}, Sib. Mat. Zh. 50, No. 1, 19--27 (2009; Zbl 1224.35245); translation in Sib. Math. J. 50, No. 1, 14--21 (2009) Full Text: EuDML EMIS