منابع مشابه
Poset Fiber Theorems
Suppose that f : P → Q is a poset map whose fibers f−1(Q≤q) are sufficiently well connected. Our main result is a formula expressing the homotopy type of P in terms of Q and the fibers. Several fiber theorems from the literature (due to Babson, Baclawski and Quillen) are obtained as consequences or special cases. Homology, Cohen-Macaulay, and equivariant versions are given, and some application...
متن کاملDefinition of Flat Poset and Existence Theorems for Recursive Call
This text includes the definition and basic notions of product of posets, chain-complete and flat posets, flattening operation, and the existence theorems of recursive call using the flattening operator. First part of the article, devoted to product and flat posets has a purely mathematical quality. Definition 3 allows to construct a flat poset from arbitrary non-empty set [12] in order to prov...
متن کاملDefinition of Flat Poset and Existence Theorems for Recursive
Reduction Systems and Idea of Knuth-Bendix Completion Algorithm By Grzegorz Bancerek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Double Series and Sums By Noboru Endou . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Dual Spaces and Hahn-Banach Theorem By Keiko Narita, Noboru Endou, and Yasunari Shidama 69 Semiring of Sets By Roland Coghetto . ...
متن کاملA Finite Word Poset
Our word posets have finite words of bounded length as their elements, with the words composed from a finite alphabet. Their partial ordering follows from the inclusion of a word as a subsequence of another word. The elemental combinatorial properties of such posets are established. Their automorphism groups are determined (along with similar result for the word poset studied by Burosch, Frank ...
متن کاملBoxicity and Poset Dimension
Let G be a simple, undirected, finite graph with vertex set V (G) and edge set E(G). A k-dimensional box is a Cartesian product of closed intervals [a1, b1]× [a2, b2]× · · · × [ak, bk]. The boxicity of G, box(G) is the minimum integer k such that G can be represented as the intersection graph of k-dimensional boxes, i.e. each vertex is mapped to a k-dimensional box and two vertices are adjacent...
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ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 2004
ISSN: 0002-9947,1088-6850
DOI: 10.1090/s0002-9947-04-03496-8