Results 21 to 30 of about 75 (75)

Homotopy type of the complex of free factors of a free group

open access: yesProceedings 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

open access: yesJournal 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

Decomposing tournaments into paths

open access: yesProceedings 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

Untwisting 3‐strand torus knots

open access: yesBulletin 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

Location of zeros for the partition function of the Ising model on bounded degree graphs

open access: yesJournal of the London Mathematical Society, Volume 101, Issue 2, Page 765-785, April 2020., 2020
Abstract The seminal Lee–Yang theorem states that for any graph the zeros of the partition function of the ferromagnetic Ising model lie on the unit circle in C. In fact, the union of the zeros of all graphs is dense on the unit circle. In this paper, we study the location of the zeros for the class of graphs of bounded maximum degree d⩾3, both in the ...
Han Peters, Guus Regts
wiley   +1 more source

Efficacy of an oral chew containing fibre and Bacillus velezensis C‐3102 in the management of anal sac impaction in dogs

open access: yesVeterinary Dermatology, Volume 36, Issue 1, Page 74-82, February 2025.
Background — Anal sac impaction is common in dogs and manual expression may be effective, yet recurrence remains a problem. To facilitate physiological emptying of the sacs, it is important to maintain a bulky stool consistency. Objectives — The study evaluated if supplementation with ProGlan, a complementary feed containing Bacillus velezensis C‐3102 ...
Marta Salichs   +2 more
wiley   +1 more source

Lower and upper bounds of shortest paths in reachability graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 57, Page 3023-3036, 2004., 2004
We prove the following property for safe marked graphs, safe conflict‐free Petri nets, and live and safe extended free‐choice Petri nets. We prove the following three results. If the Petri net is a marked graph, then the length of the shortest path is at most (|T| − 1) · |T|/2.
P. K. Mishra
wiley   +1 more source

CycleExpander to construct Directed Hamiltonian Circuit HexCycleSpanner to tighten Directed Hamiltonian Circuit

open access: yes, 2022
<p><strong>CycleExpander  to  <em>construct</em>  Directed  Hamiltonian  Circuit <br>HexCycleSpanner  to  <em>tighten</em>  Directed  Hamiltonian  Circuit ...
HALEMANE, KESHAVA PRASAD
core   +1 more source

On the Lovasz O-number of Almost Regular Graphs With Application to Erdos-Renyi Graphs [PDF]

open access: yes, 2006
AMS classifications: 05C69; 90C35 ...
Sotirov, R.; id_orcid   +3 more
core  

Method for solving a convex integer programming problem

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 44, Page 2829-2834, 2003., 2003
We consider a convex integer program which is a nonlinear version of the assignment problem. This problem is reformulated as an equivalent problem. An algorithm for solving the original problem is suggested which is based on solving the simple assignment problem via some of known algorithms.
Stefan M. Stefanov
wiley   +1 more source

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