Characterization of totally unimodular matrices
نویسندگان
چکیده
منابع مشابه
A Generalization of Tutte's Characterization of Totally Unimodular Matrices
An integral square matrix A is called principally unimodular (PU if every nonsingular principal submatrix is unimodular (that is, has determinant \1). Principal unimodularity was originally studied with regard to skew-symmetric matrices; see [2, 4, 5]; here we consider symmetric matrices. Our main theorem is a generalization of Tutte's excluded minor characterization of totally unimodular matri...
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Let p ∈ [1,∞[ and cp = maxa∈[0,1]((1 − a)ap + a(1 − a)p)1/p. We prove that the known upper bound lindiscp(A) ≤ cp for the Lp linear discrepancy of a totally unimodular matrix A is asymptotically sharp, i.e., sup A lindiscp(A) = cp. We estimate cp = p p+1 ( 1 p+1 )1/p (1+εp) for some εp ∈ [0, 2−p+2], hence cp = 1− ln p p (1+ o(1)). We also show that an improvement for smaller matrices as in the ...
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In this thesis we discuss possible generalizations of totally unimodular and network matrices. Our purpose is to introduce new classes of matrices that preserve the advantageous properties of these well-known matrices. In particular, our focus is on the polyhedral consequences of totally unimod ular matrices, namely we look for matrices that can ensure vertices that are scalable to an integral...
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Seymour’s famous decomposition theorem for regular matroids states that any totally unimodular (TU) matrix can be constructed through a series of composition operations called k-sums starting from network matrices and their transposes and two compact representation matrices B1, B2 of a certain ten element matroid. Given that B1, B2 are binet matrices we examine the k-sums of network and binet m...
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ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 1965
ISSN: 0002-9939
DOI: 10.1090/s0002-9939-1965-0180568-2