摘要Theorem 2. The infinitesimal Backlund transformnations Bλ+εBγ-1 of the sine-Gordon equation are permutable if and only if the conserred densities of the equation are in involution in pairs. This theorem reveals an intrinsie
2LUO Congwen, WANG Gaoxia Department of Mathematics, China Three Gorges University, Yichang 443002, Hubei, China.Congruence Permutable Kleene-Stone Algebras[J].Wuhan University Journal of Natural Sciences,2010,15(2):99-102.