A Hopf lemma and regularity for fractional $p-$Laplacians

Hopf's lemmas for parabolic fractional Laplacians and parabolic fractional $p$-Laplacians

“…Jin and Li [22] derived a Hopf's lemma for a fractional p-Laplacian. Chen, Li and Qi [9] obttained a Hopf's type lemma for positive weak super-solutions of the fractional p-Laplacian equations with Dirichlet conditions. So far as we aware, not much is known concerning Hopf type lemmas for parabolic equations involving nonlocal elliptic operators.…”