Exact solutions in two (2+1)-dimensional KdV-type (Sawada-Kodera and Boussinesq) equations are presented by using the bilinear method. The N-breather solution, the solution to describe the interaction between a line soliton and a y-periodic soliton, and the solution to express the interaction between two y-periodic solitons are included in our results. Detailed behavior of interactions between ...

We provide a framework to build periodic boundary conditions on the pseudosphere (or hyperbolic plane), the infinite two-dimensional Riemannian space of constant negative curvature. Starting from the common case of periodic boundary conditions in the Euclidean plane, we introduce all the needed mathematical notions and sketch a classification of periodic boundary conditions on the hyperbolic pl...