The Barenblatt solution of an evolution problem governed by a doubly nonlinear nonlocal operator

In this article, we prove existence and uniqueness of the Barenblatt solution of the evolution equation on the whole Euclidean space where the principle part is the nonlocal fractional p-Laplacian composed with a power function. Our proof generalizes methods developped by J.-L. Vazquez [Nonlinear Anal., 199 (2022), Calc. Var. Partial Differential Equations, 60 (2021)] for the evolution equation driven by the fractional p-Laplacian on the whole Euclidean space. In particular, we required an Aleksandrov symmetry principle, which can be applied to the mild solutions of the evolution equation in $L^1$ governed by the doubly nonlinear nonlocal operator, and the construction of global barrier functions. The Aleksandrov symmetry principle might be of independent interest.