Brignall, Robert; Ruškuc, Nik and Vatter, Vincent
Simple permutations: Decidability and unavoidable substructures.
Theoretical Computer Science, 391(1-2) pp. 150–163.
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 permutations: every sufficiently long simple permutation contains an alternation or oscillation of length k.
Actions (login may be required)