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133
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DM
2006
15 years 4 months ago
2006
For an oriented graph G with n vertices, let f(G) denote the minimum number of transitive subtournaments that decompose G. We prove several results on f(G). In particular, if G is...
151
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DM
2006
15 years 4 months ago
2006
Let F1, F2, . . . , Fk be graphs with the same vertex set V . A subset S V is a factor dominating set if in every Fi every vertex not in S is adjacent to a vertex in S, and a fac...
137
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FUIN
2006
15 years 4 months ago
2006
In this paper we deal with the problem of finding an optimal query execution plan in database systems. We improve the analysis of a polynomial-time approximation algorithm due to M...
118
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IPL
2008
15 years 4 months ago
2008
Suppose that D is an acyclic orientation of the graph G. An arc of D is dependent if its reversal creates a directed cycle. Let d(D) denote the number of dependent arcs in D. Defi...
124
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COMBINATORICS
2007
15 years 4 months ago
2007
Let G = (V, E) be any d-regular graph with girth g on n vertices, for d ≥ 3. This note shows that G has a maximum matching which includes all but an exponentially small fraction...