MULTICOMPONENT REACTIVE FLOWS (I) SYMMETRIZATION AND LOCAL EXISTENCE Vincent GIOVANGIGLI and Marc MASSOT Centre de Math\'ematiques Appliqu\'ees Ecole Polytechnique, 91128 Palaiseau Cedex, France We consider the equations governing multicomponent reactive flows derived from the kinetic theory of dilute polyatomic reactive gas mixtures. Using an entropy function, we derive a symmetric conservative form of the system. In the framework of Kawashima's and Shizuta's theory, we recast the resulting system into a normal form, that is, in the form of a symmetric hyperbolic-parabolic composite system. We also characterize all normal forms for symmetric systems of conservation laws such that the nullspace associated with dissipation matrices is invariant. Using a result of Vol'pert and Hudjaev, we then prove the local existence of a bounded smooth solution to the Cauchy problem. The whole paper is available as a compressed Postscript file by internet procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100) in the directory pub/RI/1996 under the name giovangigli_massot_349.jun.ps.gz or by Xmosaic or any other www client via the CMAP www server "http://blanche.polytechnique.fr/"