A Partial Order Structure on the Shellings of Lexicographically Shellable Posets.

dc.contributor.advisorHersh, Patricia
dc.contributor.authorLacina, Stephen
dc.date.accessioned2024-01-09T22:47:19Z
dc.date.available2024-01-09T22:47:19Z
dc.date.issued2024-01-09
dc.description.abstractThis dissertation has two main topics. The first is the introduction and in-depth study of a new poset theoretic structure designed to help us better understand the notion of lexicographic shellability of partially ordered sets (posets). Lexicographic shelling of posets was introduced by Bj{\"o}rner via a type of poset labeling known as an EL-labeling and was generalized by Bj{\"o}rner and Wachs to the notion of CL-labeling. We introduce and study a partial order structure on the maximal chains of any finite bounded poset $P$ which has a CL-labeling $\lambda$. We call this partial order the maximal chain descent order induced by $\lambda$, denoted $P_{\lambda}(2)$. We show that this new partial order can be thought of as the structure of the set of shellings of $P$ ``derived from $\lambda$". A motivating example is the weak order of type A. Another especially interesting class of examples produces natural partial orders on standard Young tableaux. We prove several results about the cover relations of maximal chain descent orders in general. We characterize the EL-labelings whose maximal chain descent orders have the expected cover relations, and we prove that this is the case for many important families of EL-labelings. The second main topic of this dissertation is that of determining the poset topology of two families of lattices known as $s$-weak order and the $s$-Tamari lattice.en_US
dc.identifier.urihttps://hdl.handle.net/1794/29168
dc.language.isoen_US
dc.publisherUniversity of Oregon
dc.rightsAll Rights Reserved.
dc.subjectLexicographic Shellabilityen_US
dc.subjectPoset Topologyen_US
dc.subjectTopological Combinatoricsen_US
dc.titleA Partial Order Structure on the Shellings of Lexicographically Shellable Posets.
dc.typeElectronic Thesis or Dissertation
thesis.degree.disciplineDepartment of Mathematics
thesis.degree.grantorUniversity of Oregon
thesis.degree.leveldoctoral
thesis.degree.namePh.D.

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