Positive periodic solutions for a neutral impulsive delayed Lotka–Volterra competition system with the effect of toxic substance

Based on the coincidence degree theory and its related continuation theorem as well as some a priori estimates, we explore the existence of periodic solutions with strictly positive components of a neutral delayed Lotka–Volterra competitive system with impulse. Easily verifiable sufficient criteria are established for the existence of positive periodic solution for the neutral impulsive system. When the results reduce to neutral system without impulse, they generalize the results in Yang and Cao [Positive periodic solutions of neutral Lotka–Volterra system with periodic delays, Appl. Math. Comput. 149 (2004) 661–687].