Comments on “Supersolvable frame-matroid and graphic-lift lattices” by T. Zaslavsky [European Journal of Combinatorics 22 (2001) 119]
نویسندگان
چکیده
منابع مشابه
Supersolvable Frame-matroid and Graphic-lift Lattices
A geometric lattice is a frame if its matroid, possibly after enlargement, has a basis such that every atom lies under a join of at most two basis elements. Examples include all subsets of a classical root system. Using the fact that nitary frame matroids are the bias matroids of biased graphs, we characterize modular coatoms in frames of nite rank and we describe explicitly the frames that are...
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A graph X is called almost self-complementary with respect to a perfect matching I if it is isomorphic to the graph obtained from its complement Xc by removing the edges of I. A two-graph on a vertex set Ω is a collection T of 3-subsets of Ω such that each 4-subset of Ω contains an even number of elements of T . In this paper we investigate the relationship between self-complementary two-graphs...
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Using results on Hadamard difference sets, we construct regular graphical Hadamard matrices of negative type of order 4m4 for every positive integerm. Ifm > 1, such a Hadamard matrix is equivalent to a strongly regular graph with parameters (4m4, 2m4 + m2,m4 + m2,m4 + m2). Strongly regular graphs with these parameters have been called max energy graphs, because they have maximal energy (as defi...
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Finite point configurations in projective spaces are combinatorially described by matroids, where full (finite) projective spaces correspond to connected modular matroids. Every representable matroid can in fact be extended to a modular one. However, we show that some matroids do not even have a modularly complemented extension. Enlarging the class of “ambient spaces” under consideration, we sh...
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A relatively simple proof is presented for the min-max theorem of Lovász on the graphic matroid parity problem.
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ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 2004
ISSN: 0195-6698
DOI: 10.1016/s0195-6698(03)00122-7