Sum numbers of hypertrees
نویسندگان
چکیده
منابع مشابه
Sum Complexes - a New Family of Hypertrees
A k-dimensional hypertree X is a k-dimensional complex on n vertices with a full (k−1)-dimensional skeleton and ( n−1 k ) facets such that Hk(X;Q) = 0. Here we introduce the following family of simplicial complexes. Let n, k be integers with k+1 and n relatively prime, and let A be a (k + 1)-element subset of the cyclic group Zn. The sum complex XA is the pure k-dimensional complex on the verte...
متن کاملThe sum numbers and the integral sum numbers of Cn and Wn
Let G = (V,E) be a simple graph with the vertex set V and the edge set E. G is a sum graph if there exists a labelling f of the vertices of G into distinct positive integers such that uv ∈ E if and only if f(w) = f(u) + f(v) for some vertex w ∈ V . Such a labelling f is called a sum labelling of G. The sum number σ(G) of G is the smallest number of isolated vertices which result in a sum graph ...
متن کاملMaximum Likelihood Markov Hypertrees
One popular class of such models are Markov networks, which use an undirected graph to represent dependencies among variables. Markov networks of low tree-width (i.e. having a triangulation with small cliques ) allow efficient computations, and are useful as learned probability models [8]. A well studied case is that in which the dependency structure is known in advance. In this case the underl...
متن کاملNoncrossing Hypertrees
Hypertrees and noncrossing trees are well-established objects in the combinatorics literature, but the hybrid notion of a noncrossing hypertree has received less attention. In this article I investigate the poset of noncrossing hypertrees as an induced subposet of the hypertree poset. Its dual is the face poset of a simplicial complex, one that can be identified with a generalized cluster compl...
متن کاملOn Integral Sum Numbers of Cycles
In this paper we determine that integral sum number of graph n C , namely for any integer 5 n , then 0 ) ( n C , therefore we prove that the graph ) 5 ( n Cn is an integral sum graph.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2000
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(99)00307-6