We prove that it is decidable whether a finitely based permutation class contains infinitely many simple permutations, and establish an unavoidable substructure result for simple ...
A permutation class which is closed under pattern involvement may be described in terms of its basis. The wreath product construction X Y of two permutation classes X and Y is als...
We present an algorithm running in time O(n log n) which decides if a wreathclosed permutation class Av(B) given by its finite basis B contains a finite number of simple permutati...