We theoretically investigate the co-propagation characteristics of two hollow solitons in (2+1)-dimensional nonlocal nonlinear Schrödinger equation, which can be regarded as a mathematical model of optical nonlocal nonlinear media. It is found that the two solitons always collide periodically. The influences of initial parameters (such as the initial phase, the input energy, the initial interval etc.) on the evolutions of soliton collision are analyzed in detail. A set of analytical expressions are obtained to describe these characteristic...
