Gómez-Ullate Otaiza, DavidLafortune, S.Winternitz, P.2023-06-202023-06-201999-060022-248810.1063/1.532728https://hdl.handle.net/20.500.14352/59633©1999 American Institute of Physics. The authors thank D. Levi and M. A. Rodriguez for helpful discussions. The research of S.L. and P.W. was partly supported by the NSERC of Canadá and FCAR du Québec. S. L. would like to thank the Departamento de Física Teórica II de la Universidad Complutense for their hospitality during his stay in Madrid. D.G.U.’s work was partly supported by DGES Grant No. PB95-0401. He would like to express his gratitude to the Centre de Recherches Mathématiques for their kind hospitalityThe Lie point symmetries of a coupled system of two nonlinear differential-difference equations are investigated. It is shown that in special cases the symmetry group can be infinite dimensional, in other cases up to ten dimensional. The equations can describe the interaction of two long molecular chains, each involving one type of atoms.engjournal articlehttp://dx.doi.org/10.1063/1.532728http://scitation.aip.orgopen access51-73Differential-difference-equationsFísica-Modelos matemáticosFísica matemática