Abstract:
We clarify the integrability nature of a recently found discrete equation on the square lattice with a nonstandard symmetry structure. We find its $L$–$A$ pair and show that it is also nonstandard. For this discrete equation, we construct the hierarchies of both generalized symmetries and conservation laws. This equation yields two integrable systems of hyperbolic type. The hierarchies of generalized symmetries and conservation laws are also nonstandard compared with known equations in this class.