RESONANT INTERACTIONS BETWEEN Y-PERIODIC SOLITON AND ALGEBRAIC SOLITON - SOLUTIONS TO THE KADOMTSEV-PETVIASHVILI EQUATION WITH POSITIVE DISPERSION

There are two types of singular interactions between algebraic soliton and y-periodic soliton (i.e. the array of the localized structures in the y-direction, which propagates in the x-direction): one is the res onant interaction where the algebraic soliton joins in the line of y-p eriodic soliton after collision, while the other is the extremely repu lsive interaction where the algebraic soliton affects the motion of th e y-periodic soliton infinitely apart. Both interactions are associate d with the boundary between attractive interaction and repulsive one i n the parameter space.