We constructively prove that the partially ordered set of finite permutations ordered by deletion of entries contains an infinite antichain. In other words, there exists an infini...
Partial words are finite sequences over a finite alphabet A that may contain a number of “do not know” symbols denoted by ’s. Setting A = A ∪ { }, A∗ denotes the set o...
We define a partial order on colored compositions with many properties analogous to Young’s lattice. We show that saturated chains correspond to colored permutations, and that ...