The flag f-vector is a basic combinatorial invariant of graded posets that counts the number of chains. For an Eulerian poset, its flag f-vector is efficiently encoded by a certain non-commutative polynomial, called the cd-index. In this note, we give an extensions of the cd-index which can be defined for all CW-posets that are not necessary Eulerian. The details for this work are provided in our paper (Murai and Yanagawa, Squarefree P-modules and the cd-index, Adv. Math. 265, 241–279 (2014).).
|Title of host publication||Springer INdAM Series|
|Publisher||Springer International Publishing|
|Number of pages||4|
|Publication status||Published - 2015 Jan 1|
|Name||Springer INdAM Series|
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