The relation between composability and splittability of permutation classes

A permutation class C is said to be splittable if there exist two proper subclasses , B ? such that any ? ? can red–blue colored so the red (respectively, blue) subsequence of order isomorphic an element ). The composable exists some number 1 … k written as ? ? ? for i . We answer a question Karpilovskij by showing not splittable. also give condition under which infinite must