Braam, P. J.; Duistermaat, J. J. Normal forms of real symmetric systems with multiplicity. (English) Zbl 0802.35176 Indag. Math., New Ser. 4, No. 4, 407-421 (1993). A normal form is given for real symmetric systems of linear partial differential operators where the principal symbol has a two-dimensional kernel under assumptions which apply to the generic case. The model is microlocally the following \(2\times 2\) system: \[ \left( \begin{matrix} D_ 1 + D_ 2 & x_ 2D_ 3\\ x_ 2D_ 3 & \pm(D_ 1 - D_ 2) \end{matrix} \right) \] with \(D_ j = - i \partial/ \partial x_ j\). Reviewer: B.Helffer (Paris) Cited in 1 ReviewCited in 12 Documents MSC: 35S30 Fourier integral operators applied to PDEs 35A27 Microlocal methods and methods of sheaf theory and homological algebra applied to PDEs Keywords:normal form; real symmetric systems of linear partial differential operators × Cite Format Result Cite Review PDF Full Text: DOI References: [1] Arnol’d, V. I., On the interior scaterring of waves defined by hyperbolic variational principles, Journal of Geometry and Physics, 5, 3, 305-315 (1988) · Zbl 0699.35199 [2] Arnol’d, V. I., Surfaces defined by hyperbolic equations, Math Notes, 44, 112, 489-497 (1988) · Zbl 0667.58048 [3] Arnol’d, V. I., Singularities of caustics and wave fronts (1991), Kluwer · Zbl 0734.53001 [4] Borel, E., Sur quelques points de la théorie des fonctions, Ann. Sci. École Norm. Sup., 12, 9-55 (1985) · JFM 26.0429.03 [5] Born, M.; Wolf, E., Principles of Optics (1959), Pergamon Press [6] Burridge, R., The singularity on the plane lids of the wave surface of elastic media with cubic symmetry, Quart. Jour. Mech. and Applied Math., XX, 41-56 (1967), part 1 · Zbl 0189.26501 [7] Dencker, N. - On the propagation of polarization in conical refraction. Preprint.; Dencker, N. - On the propagation of polarization in conical refraction. Preprint. · Zbl 0669.35116 [8] Dencker, N., On the propagation of polarization sets for systems of real principal type, Journal of Functional Analysis, 46, 351-372 (1982) · Zbl 0487.58028 [9] Hamilton, W. R., Third supplement to an essay on the theory of rays, Trans. Roy. Irish Ac., 17, 1, 1-144 (1937) [10] Holm, P., Generic elastic media, Physica Scripta, T44, 122-127 (1992) [11] Ivrii, V. Ja., On wave fronts of solutions of the system of crystal optics, Soviet Math. Dokl., 18, 139-141 (1977) · Zbl 0369.35041 [12] Ivrii, V. Ja., Wave fronts of solutions of symmetric pseudodifferential systems, Siberian Math. J., 20 (1979) · Zbl 0369.35060 [13] Duistermaat, J. J.; Hörmander, L., Fourier integral operators II, Acta. Math., 128, 183-269 (1972) · Zbl 0232.47055 [14] John, F., Algebraic conditions for hyperbolicity of systems of partial differential operators, Comm. Pure. Appl. Math., 31, 787-793 (1978) · Zbl 0397.35041 [15] Khesin, B. A., Singularities of light hypersurfaces and hyperbolicity sets for systems of pde’s, (Arnol’d, V. I., Theory of singularities and its applications, Volume 1 (1990), AMS Providence), 105-118, of Adv. Sov. Mathematics · Zbl 0747.35019 [16] Kline, M.; Kay, I. W., Electromagnetic Theory and Geometric Optics (1964), Wiley [17] Hörmander, L., The Analysis of Linear Partial Differential Operators III (1980), Springer [18] Hörmander, L., Hyperbolic systems with double characteristics, Comm. Pure Appl. Math., 46, 261-301 (1993) · Zbl 0803.35082 [19] Lax, P. D., The multiplicity of eigenvalues, Bull. AMS, 6, 213-215 (1982) · Zbl 0483.15006 [20] Lifschitz, E. M.; Landau, L. D.; Pitaevskii, L. P., Electrodynamics of Continuous Media, Volume 8 (1984), Pergamon Press, of Course of Theoretical Physics [21] Melrose, R. B.; Uhlmann, G. A., Microlocal structure of involutive conical refraction, Duke Math. J., 46 (1979) · Zbl 0422.58026 [22] Nuij, W., A note on hyperbolic polynomials, Math. Scand., 23, 69-72 (1968) · Zbl 0189.40803 [23] Roels, J.; Weinstein, A., Functions whose poisson brackets are constants, Journal of Meth. Phys., 12, 8, 1482-1486 (1971) · Zbl 0226.58002 This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.