نتایج جستجو برای: cyclic s poset

تعداد نتایج: 802528  

2004
W. T. TROTTER

We prove that every height-2 finite poset with three or more points has an incomparable pair (.x, J) such that the proportion of all linear extensions of the poset in which s is less than y is between l/3 and 213. A related result of Koml6s says that the containment interval [l/3,2/3] shrinks to [l/2, l/2] in the limit as the width of height-2 posets becomes large. We conjecture that a poset de...

Journal: :CoRR 2012
Filippo Disanto Luca Ferrari Simone Rinaldi

We introduce a partial order structure on the set of interval orders of a given size, and prove that such a structure is in fact a lattice. We also provide a way to compute meet and join inside this lattice. Finally, we show that, if we restrict to series parallel interval order, what we obtain is the classical Tamari poset.

1997
William T. Trotter

Over the past 15 years, Ramsey theoretic techniques and concepts have been applied with great success to partially ordered sets. In the last year alone, four new applications of Ramsey theory to posets have produced solutions to some challenging combinatorial problems. First, Kierstead and Trotter showed that dimension for interval orders can be characterized by a single ramsey trail by proving...

2006
Jean-Louis Loday JEAN-LOUIS LODAY André Joyal

We show that a minimal triangulation of the associahedron (Stasheff polytope) of dimension n is made of (n+ 1)n−1 simplices. We construct a natural bijection with the set of parking functions from a new interpretation of parking functions in terms of shuffles. Introduction The Stasheff polytope, also known as the associahedron, is a polytope which comes naturally with a poset structure on the s...

1996
Kazutoshi Ando Satoru Fujishige Toshio Nemoto

The concept of signed poset has recently been introduced by V. Reiner as a generalization of that of ordinary poset (partially ordered set). We consider the problem of finding a minimum-weight ideal of a signed poset. We show a representation theorem that there exists a bijection between the set of all the ideals of a signed poset and the set of all the "reduced ideals" (defined here) of the as...

Journal: :International Journal of Algebra and Computation 2021

Finite smooth digraphs, that is, finite directed graphs without sources and sinks, can be partially ordered via pp-constructability. We give a complete description of this poset and, in particular, we prove it is distributive lattice. Moreover, show order to separate two digraphs our suffices the polymorphism clone one satisfies prime cyclic loop condition not satisfied by other. Furthermore, c...

Journal: :Journal of Algebraic Combinatorics 2021

We introduce a family of posets which generate Lie poset subalgebras $$A_{n-1}=\mathfrak {sl}(n)$$ whose index can be realized topologically. In particular, if $$\mathcal {P}$$ is such toral poset, then it has simplicial realization homotopic to wedge sum d one-spheres, where the corresponding type-A algebra $$\mathfrak {g}_A(\mathcal {P})$$ . Moreover, when Frobenius, its spectrum binary, that...

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده ریاضی 1390

می دانیم در رسته s – سیستم ها ، شی انژکتیو موجود است ، نشان می دهیم مجموعه های مرتب جزئی و s - سیستم های مرتب ، شی انژکتیو غیر بدیهی ندارند و همچنین مجموعه های مرتب جزئی انژکتیو منظم دقیقا مجموعه های مرتب جزئی کامل هستند. سپس نشان می دهیم که هر سیستم مرتب انژکتیو منظم کامل است و عکس آن نیز در حالتی که s - گروه جزئی مرتب باشد برقرار می شود. در این پایان نامه ، ابتدا مفاهیم مورد نیاز از مجموعه ه...

Journal: :J. Comb. Theory, Ser. A 2011
Jang Soo Kim

We give combinatorial proofs of the formulas for the number of multichains in the k-divisible noncrossing partitions of classical types with certain conditions on the rank and the block size due to Krattenthaler and Müller. We also prove Armstrong’s conjecture on the zeta polynomial of the poset of k-divisible noncrossing partitions of type A invariant under the 180◦ rotation in the cyclic repr...

Journal: :Electr. J. Comb. 2015
Abhishek Methuku Casey Tompkins

We introduce a method of decomposing the family of intervals along a cyclic permutation into chains to determine the size of the largest family of subsets of [n] not containing one or more given posets as a subposet. De Bonis, Katona and Swanepoel determined the size of the largest butterfly-free family. We strengthen this result by showing that, for certain posets containing the butterfly pose...

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