Characterising inflations of monotone grid classes of permutations
Michael Albert, Aistis Atminas, Robert Brignall · arXiv (Cornell University) · 2017
We characterise those permutation classes whose simple permutations are monotone griddable. This characterisation is obtained by identifying a set of nine substructures, at least one of which must occur in any simple permutation containing a long sum of 21s.