“…They also obtained a global-in-time solution under u 0 (x) ≤ c|x| −(2−γ)/(p−1) if p > p γ and c > 0 small. For related results, see [1,3,7,8,9,10,13,14,15,18,19]. Subsequently, the first author and Sierż ' ega [12] examined necessary conditions of initial data for the existence of solutions including a fractional case.…”