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We prove that the crossing number of a graph decays in a " continuous fashion " in the following sense. For any ε > 0 there is a δ > 0 such that for a sufficiently large n, every graph G with n vertices and m ≥ n 1+ε edges, has a subgraph G ′ of at most (1 − δ)m edges and crossing number at least (1 − ε)cr(G). This generalizes the result of J. Fox and Cs.(More)
Let X be a set of points in general position in the plane. General position means that no three points lie on a line and no two points have the same x-coordinate. Y ⊆ X is a cup, resp. cap, if the points of Y lie on the graph of a convex, resp. concave function. Denote the points of Y by p 1 , p 2 ,. .. , p m according to the increasing x-coordinate. The(More)
For an integer <i>h</i> &#8805; 1, an <i>elementary h-route flow</i> is a flow along <i>h</i> edge disjoint paths between a source and a sink, each path carrying a unit of flow, and a single commodity <i>h-route flow</i> is a non-negative linear combination of elementary <i>h</i>-flows. An instance of a <i>single source multicommodity flow problem</i> for a(More)
AIM To provide an overview of gambling and associated problems in the Czech Republic, including an overview of the historical context, legislation, prevalence, treatment and research base and agenda. METHODS A review of literature and relevant sources. RESULTS The trajectory of gambling patterns in the territory of the Czech Republic in the 20th century(More)
For an integer h ≥ 1, an elementary h-route flow is a flow along h edge disjoint paths between a source and a sink, each path carrying a unit of flow, and a single commodity h-route flow is a non-negative linear combination of elementary h-route flows. An instance of a single source multicommodity flow problem for a In the single source multicommodity(More)
For an integer h ≥ 1, an elementary h-route flow is a flow along h edge disjoint paths between a source and a sink, each path carrying a unit of flow, and a single commodity h-route flow is a non-negative linear combination of elementary h-route flows. An instance of a single source multicommodity flow problem for a graph G = (V, E) consists of a source(More)