The conservation laws of several 2+1 dimensional semi-discrete equations

In this paper, we further develop and enrich the results on conservation laws obtained in Zhu (2003) and present two forms of conservation laws in different directions. In addition, we obtain Lax pairs from Bäcklund transformations for two existing equations. By solving the corresponding Lax pairs, we derive infinitely many conservation laws for several 2+1 dimensional semi-discrete equations in a systematic way.