Aratyn, H.Nissimov, E.Pacheva, S.Zimerman, A. H. [UNESP]2014-05-272014-05-271994-12-01Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, v. 341, n. 1, p. 19-30, 1994.0370-2693http://hdl.handle.net/11449/64501We show that the 2-matrix string model corresponds to a coupled system of 2 + 1-dimensional KP and modified KP ((m)KP2+1) integrable equations subject to a specific symmetry constraint. The latter together with the Miura-Konopelchenko map for (m)KP2+1 are the continuum incarnation of the matrix string equation. The (m)KP2+1 Miura and Backhand transformations are natural consequences of the underlying lattice structure. The constrained (m)KP2+1 system is equivalent to a 1 + 1-dimensional generalized KP-KdV hierarchy related to graded SL(3,1). We provide an explicit representation of this hierarchy, including the associated W(2,1)-algebra of the second Hamiltonian structure, in terms of free currents.19-30engArtigo10.1016/0370-2693(94)01255-5Acesso restrito2-s2.0-00116499738215976645016606