منابع مشابه
Cuts and penalties : Comment on ‘ ‘ Clustering of ultrahigh energy cosmic rays and their sources ’ ’
The identification of the sources of the ultrahigh energy cosmic rays ~UHECRs! is a key to understanding their nature. The observed small-scale clustering of UHECRs @2–5# suggests that the already existing data @3,6,7# may contain information sufficient to take the first steps in this direction. In a series of papers @8–14# we have shown that there exist significant correlations between the arr...
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A short proof of a difficult theorem of P.D. Seymour on grafts with the max-flow min-cut property is given.
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We recently introduced the watershed cuts, a notion of watershed in edge-weighted graphs. In this paper, we propose a new thinning paradigm to compute them. More precisely, we introduce a new transformation, called border thinning, that lowers the values of edges that match a simple local configuration until idempotence and prove the equivalence between the cuts obtained by this transformation ...
متن کاملOn disconnected cuts and separators
For a connected graph G = (V,E), a subset U ⊆ V is called a disconnected cut if U disconnects the graph and the subgraph induced by U is disconnected as well. A natural condition is to impose that for any u ∈ U the subgraph induced by (V \U)∪{u} is connected. In that case U is called a minimal disconnected cut. We show that the problem of testing whether a graph has a minimal disconnected cut i...
متن کاملOn Hilbert bases of cuts
A Hilbert basis is a set of vectors X ⊆ R such that the integer cone (semigroup) generated by X is the intersection of the lattice generated by X with the cone generated by X. Let H be the class of graphs whose set of cuts is a Hilbert basis in R (regarded as {0, 1}-characteristic vectors indexed by edges). We show that H is not closed under edge deletions, subdivisions, nor 2-sums. Furthermore...
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ژورنال
عنوان ژورنال: Nature
سال: 1982
ISSN: 0028-0836,1476-4687
DOI: 10.1038/300568c0