Myrto Kallipoliti ; Martina Kubitzke
-
Double homotopy Cohen-Macaulayness for the poset of injective words and the classical NC-partition lattice
dmtcs:2935 -
Discrete Mathematics & Theoretical Computer Science,
January 1, 2011,
DMTCS Proceedings vol. AO, 23rd International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC 2011)
-
https://doi.org/10.46298/dmtcs.2935
Double homotopy Cohen-Macaulayness for the poset of injective words and the classical NC-partition latticeArticle
Authors: Myrto Kallipoliti 1,2; Martina Kubitzke 3
0000-0003-2188-6552##NULL
Myrto Kallipoliti;Martina Kubitzke
1 Department of Mathematics [Athens]
2 Erwin Schrödinger Institute for Mathematical Physics
3 Fakultät für Mathematik [Wien]
In this paper we study topological properties of the poset of injective words and the lattice of classical non-crossing partitions. Specifically, it is shown that after the removal of the bottom and top elements (if existent) these posets are doubly Cohen-Macaulay. This extends the well-known result that those posets are shellable. Both results rely on a new poset fiber theorem, for doubly homotopy Cohen-Macaulay posets, which can be considered as an extension of the classical poset fiber theorem for homotopy Cohen-Macaulay posets.