Stability of transition waves and positive entire solutions of Fisher-KPP equations with time and space dependence

Abstract: This paper is concerned with the stability of transition waves and strictly positive entire solutions of random and nonlocal dispersal evolution equations of Fisher-KPP type with general time and space dependence, including time and space periodic or almost periodic dependence as special cases. We first show the existence, uniqueness, and stability of strictly positive entire solutions of such equations. Next, we show the stability of uniformly continuous transition waves connecting the unique strictly positive entire solution and the trivial solution zero and satisfying certain decay property at the end close to the trivial solution zero (if it exists). The existence of transition waves has been studied in [34, 39, 45, 46, 61] for random dispersal Fisher-KPP equations with time and space periodic dependence, in [41, 42, 43, 51, 52, 53, 58, 63] for random dispersal Fisher-KPP equations with quite general time and/or space dependence, and in [17, 48, 56] for nonlocal dispersal Fisher-KPP equations with time and/or space periodic dependence. The stability result established in this paper implies that the transition waves obtained in many of the above mentioned papers are asymptotically stable. Up to the author's knowledge, it is the first time that the stability of transition waves of Fisher-KPP equations with both time and space dependence is studied.