“…In such cases, the solution operators become multi-valued maps, which results in that the classical attractor theory based on the semigroup of operators becomes useless. Hence the theory on the attractor of multi-valued operators is important for it allow us to continue to study the longtime behavior of the solutions no matter we have uniqueness or not, and this topic has been extensively investigated over the last one and a half decades, one can see [3,6,9,23,24,25,26,31] and references therein.…”