2005/03/30 by Lizhou Chen, Chen, Lizhou
Mathematics · Physics and Astronomy · #35A30 #37K05 #37K10 #Analysis of PDEs (math.AP) #FOS: Mathematics #FOS: Physical sciences #Mathematical Physics (math-ph) #math-ph #math.AP #math.MP #msc:35A30 #msc:37K05 #msc:37K10
paper · pdf · doi:10.48550/arxiv.math-ph/0503070
contents changed, 11 pages
arxiv created 2005/11/10 · arxiv updated 2009/12/01
We extend the integrability analysis for scalar evolution equations of type ut=um+f(u,u1,...,um-1) from the case that the right hand side is a λ-homogeneous formal power series to the case that it is a nonhomogeneous formal power series. It is proved that the existence of one nontrivial symmetry implies the existence of infinitely many, more precisely, the orders of the infinite integrable hierarchy must be one of the following cases: ℤ++1, 2ℤ++1, 6ℤ+±1, or 6ℤ++1. Moreover, if the nonlinear part of the equation is a polynomial of order less than m-1, we show that any generalized symmetry is also of polynomial type.