Fundamental solutions for a class of Isaacs integral operators (Q541551)

In the very interesting paper under review, the authors study the existence of fundamental solutions for a class of Isaacs integral operators which includes the extremal operators defined by \textit{L. CaffarellI} and \textit{L. Silvestre} in [Commun. Pure Appl. Math. 62, No.~5, 597--638 (2009; Zbl 1170.45006)], fractional Pucci operators and a class of non-convex (concave) operators. Combining these fundamental solutions with the comparison principle for non-local operators, the authors derive Liouville type theorems for the corresponding operators.