Results 21 to 30 of about 91 (88)
Injectivity results for coarse homology theories
Proceedings of the London Mathematical Society, Volume 121, Issue 6, Page 1619-1684, December 2020., 2020 Abstract We show injectivity results for assembly maps using equivariant coarse homology theories with transfers. Our method is based on the descent principle and applies to a large class of linear groups or, more generally, groups with finite decomposition complexity.
Ulrich Bunke +3 more
wiley +1 more source
Trees Whose Even-Degree Vertices Induce a Path are Antimagic
Discussiones Mathematicae Graph Theory, 2022 An antimagic labeling of a connected graph G is a bijection from the set of edges E(G) to {1, 2, . . ., |E(G)|} such that all vertex sums are pairwise distinct, where the vertex sum at vertex v is the sum of the labels assigned to edges incident to v.
Lozano Antoni +3 more
doaj +1 more source
Homotopy type of the complex of free factors of a free group
Proceedings of the London Mathematical Society, Volume 121, Issue 6, Page 1737-1765, December 2020., 2020 Abstract We show that the complex of free factors of a free group of rank n⩾2 is homotopy equivalent to a wedge of spheres of dimension n−2. We also prove that for n⩾2, the complement of (unreduced) Outer space in the free splitting complex is homotopy equivalent to the complex of free factor systems and moreover is (n−2)‐connected.
Benjamin Brück, Radhika Gupta
wiley +1 more source
When products of projections diverge
Journal of the London Mathematical Society, Volume 102, Issue 1, Page 345-367, August 2020., 2020 Abstract Slow convergence of cyclic projections implies divergence of random projections and vice versa. Let L1,L2,⋯,LK be a family of K closed subspaces of a Hilbert space. It is well known that although the cyclic product of the orthogonal projections on these spaces always converges in norm, random products might diverge.
Eva Kopecká
wiley +1 more source
On the Optimality of 3-Restricted Arc Connectivity for Digraphs and Bipartite Digraphs
Discussiones Mathematicae Graph Theory, 2022 Let D be a strong digraph. An arc subset S is a k-restricted arc cut of D if D − S has a strong component D′ with order at least k such that D\V (D′) contains a connected subdigraph with order at least k.
Zhang Yaoyao, Meng Jixiang
doaj +1 more source
Decomposing tournaments into paths
Proceedings of the London Mathematical Society, Volume 121, Issue 2, Page 426-461, August 2020., 2020 Abstract We consider a generalisation of Kelly's conjecture which is due to Alspach, Mason, and Pullman from 1976. Kelly's conjecture states that every regular tournament has an edge decomposition into Hamilton cycles, and this was proved by Kühn and Osthus for large tournaments. The conjecture of Alspach, Mason, and Pullman asks for the minimum number
Allan Lo +3 more
wiley +1 more source
The complexity of the connected graph access structure on seven participants
Journal of Mathematical Cryptology, 2017 In this paper, we study an important problem in secret sharing that determines the exact value or bound for the complexity. First, we use the induced subgraph complexity of the graph G with access structure Γ to obtain a lower bound on the complexity of ...
Hadian Dehkordi Massoud, Safi Ali
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Untwisting 3‐strand torus knots
Bulletin of the London Mathematical Society, Volume 52, Issue 3, Page 429-436, June 2020., 2020 Abstract We prove that the signature bound for the topological 4‐genus of 3‐strand torus knots is sharp, using McCoy's twisting method. We also show that the bound is off by at most 1 for 4‐strand and 6‐strand torus knots, and improve the upper bound on the asymptotic ratio between the topological 4‐genus and the Seifert genus of torus knots from 2/3 ...
S. Baader, I. Banfield, L. Lewark
wiley +1 more source
On q-Power Cycles in Cubic Graphs
Discussiones Mathematicae Graph Theory, 2017 In the context of a conjecture of Erdős and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e., with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic
Bensmail Julien
doaj +1 more source
On Conditional Connectivity of the Cartesian Product of Cycles
Discussiones Mathematicae Graph Theory, 2023 The conditional h-vertex (h-edge) connectivity of a connected graph H of minimum degree k > h is the size of a smallest vertex (edge) set F of H such that H − F is a disconnected graph of minimum degree at least h. Let G be the Cartesian product of r ≥ 1
Saraf J.B., Borse Y.M., Mundhe Ganesh
doaj +1 more source