2000/12/10 by A. Sergyeyev, Sergyeyev, A.
Physics and Astronomy · #Exactly Solvable and Integrable Systems (nlin.SI) #FOS: Physical sciences #nlin.SI
paper · pdf · doi:10.48550/arxiv.nlin/0012016
10 pages, LaTeX, talk at NATO ARW "Noncommutative Structures in Mathematics and Physics" (September 24-27, 2000, Kiev, Ukraine)
arxiv created 2000/12/10 · arxiv updated 2009/11/30
We present easily verifiable sufficient conditions of time-independence and commutativity for local and nonlocal symmetries for a large class of homogeneous (1+1)-dimensional evolution systems. In contrast with the majority of known results, the verification of our conditions does not require the existence of master symmetry or hereditary recursion operator for the system in question. We also give simple sufficient conditions for the existence of infinite sets of time-independent symmetries for homogeneous (1+1)-dimensional evolution systems within slightly modified master symmetry approach.