“…For applications, one can consider new classes of problems with degeneracy, feedback control problems, problems on manifolds, problems with delay, stochastic partial differential equations, etc. (see Balibrea et al [2]; Hu and Papageorgiou [3]; Gasinski and Papageorgiou [5]; Kasyanov [15]; Kasyanov, Toscano, and Zadoianchuk [17]; Mel'nik and Valero [21]; Denkowski, Migórski, and Papageorgiou [13]; Gasinski and Papageorgiou [5]; Zgurovsky et al [29,30]; etc.) involving differential operators of pseudomonotone type and the corresponding choice of the phase spaces.…”