منابع مشابه
Quotients of dilworth truncations
Sufficient conditions are given for an elementary quotient of the kth Dilworth truncation of a matroid M to be the kth Dilworth truncation of a quotient of M. As special cases, contractions of Dilworth truncations and principal truncations by connected flats of Dilworth truncations are characterised as Dilworth truncations of certain matroids. As an application of the theory it is shown that th...
متن کاملGeneric Rigidity Matroids with Dilworth Truncations
We prove that the linear matroid that defines the generic rigidity of d-dimensional bodyrod-bar frameworks (i.e., structures consisting of disjoint bodies and rods mutually linked by bars) can be obtained from the union of ( d+1 2 ) copies of a graphic matroid by applying variants of Dilworth truncation operations nr times, where nr denotes the number of rods. This result leads to an alternativ...
متن کاملMatroid matching with Dilworth truncation
Let H = (V, E) be a hypergraph and let k ≥ 1 and l ≥ 0 be fixed integers. LetM be the matroid with ground-set E s.t. a set F ⊆ E is independent if and only if each X ⊆ V with k|X| − l ≥ 0 spans at most k|X| − l hyperedges of F . We prove that if H is dense enough, thenM satisfies the double circuit property, thus the min-max formula of Dress and Lovász on the maximum matroid matching holds forM...
متن کاملDILWORTH and GIRARDI
For an arbitrary innnite-dimensional Banach space X, we construct examples of strongly-measurable X-valued Pettis integrable functions whose indefinite Pettis integrals are nowhere weakly diierentiable; thus, for these functions the Lebesgue Diierentiation Theorem fails rather spectacularly. We also relate the degree of nondiierentiability of the indeenite Pettis integral to the cotype of X, fr...
متن کاملEstimation of Tensor Truncations Estimation of Tensor Truncations
Tensor truncation techniques are based on singular value decompositions. Therefore, the direct error control is restricted to l or L norms. On the other hand, one wants to approximate multivariate (grid) functions in appropriate tensor formats in order to perform cheap pointwise evaluations, which require l ∞ or L∞ error estimates. Due to the huge dimensions of the tensor spaces, a direct estim...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series B
سال: 1990
ISSN: 0095-8956
DOI: 10.1016/0095-8956(90)90064-7