منابع مشابه
Still another triangle-free infinite-chromatic graph
We give a new example of a triangle-free cc-chromatic graph: the vertices of G form a oox oo matrix, V(G) = [vi,i], i, j = 1, 2, ... The vertex vi,i is connected with every vertex of the ( i + j)th column. G is triangle-free: if A has the smallest column-index among {A, B, C}c V(G) and AB, ACEE(G), then B, Care in the same column so BC¢E(G). G is infinite-chromatic: ~ ~ {1, 2, ... } denotes the...
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A straight line triangle representation (SLTR) of a planar graph is a straight line drawing such that all the faces including the outer face are triangles. Such a drawing can be viewed as a tessellation of a triangle with triangles where the input graph is the skeletal structure. A characterization based on flat angle assignments, i.e., selections of angles of the graph that are of size π in th...
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The study of Genocchi numbers, it is claimed, goes back to Euler. In what sense that is true is somewhat unclear, but during the last two or three decades the Genocchi numbers have been studied by Dumont and some collaborators [2–7]. In recent years there has been a flurry of activity in this field, viz. [1, 9–13]. The Genocchi numbers are cousins to the Euler numbers which count the alternatin...
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We study a family of Teichmüller curves T (n,m) constructed by Bouw and Möller, and previously by Veech and Ward in the cases n = 2, 3. We simplify the proof that T (n,m) is a Teichmüller curve, avoiding the use Möller’s characterization of Teichmüller curves in terms of maximally Higgs bundles. Our key tool is a description of the period mapping of T (n,m) in terms of Schwarz triangle mappings...
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The unitarity triangle can be determined by means of two measurements of its sides or angles. Assuming the same relative errors on the angles (α, β, γ) and the sides (Rb, Rt), we find that the pairs (γ, β) and (γ,Rb) are most efficient in determining ( ̺̄, η̄) that describe the apex of the unitarity triangle. They are followed by (α, β), (α,Rb), (Rt, β), (Rt, Rb) and (Rb, β). As the set |Vus|, |Vc...
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ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 2012
ISSN: 0002-9939,1088-6826
DOI: 10.1090/s0002-9939-2012-11379-6