Generalized parking functions, descent numbers, and chain polytopes of ribbon posets

dc.creatorChebikin, Denis
dc.creatorPostnikov, Alexander
dc.date2008-06-03
dc.date.accessioned2026-07-07T09:42:23Z
dc.date.available2026-07-07T09:42:23Z
dc.descriptionWe consider the inversion enumerator I_n(q), which counts labeled trees or, equivalently, parking functions. This polynomial has a natural extension to generalized parking functions. Substituting q = -1 into this generalized polynomial produces the number of permutations with a certain descent set. In the classical case, this result implies the formula I_n(-1) = E_n, the number of alternating permutations. We give a combinatorial proof of these formulas based on the involution principle. We also give a geometric interpretation of these identities in terms of volumes of generalized chain polytopes of ribbon posets. The volume of such a polytope is given by a sum over generalized parking functions, which is similar to an expression for the volume of the parking function polytope of Pitman and Stanley.
dc.description11 pages, 1 figure
dc.identifierhttps://arxiv.org/abs/0806.0440
dc.identifierhttp://arxiv.org/abs/0806.0440
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/162163
dc.subjectCombinatorics
dc.subject05A19, 52B05
dc.titleGeneralized parking functions, descent numbers, and chain polytopes of ribbon posets
dc.typetext

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