منابع مشابه
The Connection between the Number of Realizations for Degree Sequences and Majorization
The graph realization problem is to find for given nonnegative integers a1, . . . , an a simple graph (no loops or multiple edges) such that each vertex vi has degree ai. Given pairs of nonnegative integers (a1, b1), . . . , (an, bn), (i) the bipartite realization problem ask whether there is a bipartite graph (no loops or multiple edges) such that vectors (a1, ..., an) and (b1, ..., bn) corres...
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While attempting to classify partial linear spaces produced during the execution of an extension of Stinson’s hill-climbing algorithm a new problem arises, that of generating all graphical degree sequences that are diamond-free (i.e. have no diamond as subgraph) and satisfy additional constraints. We formalize this new problem, propose a constraint programming solution and list all satisfying d...
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The problem of efficiently characterizing degree sequences of simple hypergraphs is a fundamental long-standing open problem in Graph Theory. Several results are known for restricted versions of this problem. This paper adds to the list of sufficient conditions for a degree sequence to be hypergraphic. This paper proves a combinatorial lemma about cyclically permuting the columns of a binary ta...
متن کاملDegree sequences of multigraphs
Let a, b and n be integers, n ≥ 1 and b ≥ a ≥ 0. Let an (a, b, n)-graph defined as a loopless graph G(a, b, n) on n vertices {V1, . . . , Vn}, in which Vi and Vj are connected with at least a and at most b (directed or undirected) edges. If G(a, b, n) is directed, then it is called (a, b, n)-digraph and if it is undirected, then it is called (a, b, n)undigraph. Landau in 1953 published an algor...
متن کاملOptimization over Degree Sequences
We introduce and study the problem of optimizing arbitrary functions over degree sequences of hypergraphs and multihypergraphs. We show that over multihypergraphs the problem can be solved in polynomial time. For hypergraphs, we show that deciding if a given sequence is the degree sequence of a 3-hypergraph is computationally prohibitive, thereby solving a 30 year long open problem. This implie...
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ژورنال
عنوان ژورنال: Linear Algebra and its Applications
سال: 1994
ISSN: 0024-3795
DOI: 10.1016/0024-3795(94)90349-2