منابع مشابه
Characterizations of Transversal and Fundamental Transversal Matroids
A result of Mason, as refined by Ingleton, characterizes transversal matroids as the matroids that satisfy a set of inequalities that relate the ranks of intersections and unions of nonempty sets of cyclic flats. We prove counterparts, for fundamental transversal matroids, of this and other characterizations of transversal matroids. In particular, we show that fundamental transversal matroids a...
متن کاملTransversal Lattices
A flat of a matroid is cyclic if it is a union of circuits; such flats form a lattice under inclusion and, up to isomorphism, all lattices can be obtained this way. A lattice is a Tr-lattice if all matroids whose lattices of cyclic flats are isomorphic to it are transversal. We investigate some sufficient conditions for a lattice to be a Tr-lattice; a corollary is that distributive lattices of ...
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1. Introduction. Transversal theory is a branch of combinatorial mathematics which is only just beginning to emerge as a reasonably connected and coherent subject. Whether this is yet rich enough or mature enough to be called a 'theory' may be a matter for debate; indeed, it is by no means certain that this part of mathematics may not finally be classified under some broader, more comprehensive...
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We continue the investigation of validity of Hall’s theorem in the case of the Loeb space L(H) of an internal, uniformly distributed, hyperfinite measure space H = (Ω,A, μ) initiated in1992 by the author. Some new classes of graphs are introduced for which the measure theoretic version of Hall’s theorem still holds.
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Contact structures on manifolds and Legendrian and transversal knots in them are very natural objects, born over two centuries ago, in the work of Huygens, Hamilton and Jacobi on geometric optics and work of Lie on partial differential equations. They touch on diverse areas of mathematics and physics, and have deep connections with topology and dynamics in low dimensions. The study of Legendria...
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ژورنال
عنوان ژورنال: URBANA: Revista Eletrônica do Centro Interdisciplinar de Estudos sobre a Cidade
سال: 2016
ISSN: 1982-0569
DOI: 10.20396/urbana.v7i2.8642595