ORCID Profile
0000-0002-7557-6886
Current Organisation
University of Oxford
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Publisher: Springer Berlin Heidelberg
Date: 2002
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 07-1997
Publisher: World Scientific Pub Co Pte Lt
Date: 10-2016
DOI: 10.1142/S0218216516420116
Abstract: We show that an edge-dominating cycle in a [Formula: see text]-free graph can be found in polynomial time this implies that every [Formula: see text]-tough [Formula: see text]-free graph admits a [Formula: see text]-walk, and it can be found in polynomial time. For this class of graphs, this proves a long-standing conjecture due to Jackson and Wormald [[Formula: see text]-walks of graphs, Australas. J. Combin. 2 (1990) 135–146]. Furthermore, we prove that for any [Formula: see text] every [Formula: see text]-tough [Formula: see text]-free graph is prism-Hamiltonian and give an effective construction of a Hamiltonian cycle in the corresponding prism, along with few other similar results.
Publisher: Elsevier BV
Date: 04-2009
Publisher: Springer Science and Business Media LLC
Date: 04-2005
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 07-1990
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2013
Publisher: Springer Science and Business Media LLC
Date: 17-06-2009
Publisher: Springer Berlin Heidelberg
Date: 2001
Publisher: Springer Science and Business Media LLC
Date: 18-10-2012
Publisher: Cambridge University Press
Date: 21-10-1993
Publisher: Wiley
Date: 05-1999
Publisher: Springer Science and Business Media LLC
Date: 06-1995
DOI: 10.1007/BF01263615
Publisher: Elsevier BV
Date: 07-2001
Publisher: Springer US
Date: 26-09-2009
Publisher: Springer Science and Business Media LLC
Date: 05-07-2014
Publisher: Wiley
Date: 08-1996
DOI: 10.1112/JLMS/54.1.16
Publisher: Scuola Normale Superiore
Date: 2013
Publisher: Springer Berlin Heidelberg
Date: 2002
Publisher: Elsevier BV
Date: 04-2014
Publisher: Springer Science and Business Media LLC
Date: 11-1992
DOI: 10.1007/BF00053382
Publisher: AI Access Foundation
Date: 27-12-2018
DOI: 10.1613/JAIR.1.11270
Abstract: A key issue in cooperative game theory is coalitional stability, usually captured by the notion of the core---the set of outcomes that are resistant to group deviations. However, some coalitional games have empty cores, and any outcome in such a game is unstable. We investigate the possibility of stabilizing a coalitional game by using subsidies. We consider scenarios where an external party that is interested in having the players work together offers a supplemental payment to the grand coalition, or, more generally, a particular coalition structure. This payment is conditional on players not deviating from this coalition structure, and may be ided among the players in any way they wish. We define the cost of stability as the minimum external payment that stabilizes the game. We provide tight bounds on the cost of stability, both for games where the coalitional values are nonnegative (profit-sharing games) and for games where the coalitional values are nonpositive (cost-sharing games), under natural assumptions on the characteristic function, such as superadditivity, anonymity, or both. We also investigate the relationship between the cost of stability and several variants of the least core. Finally, we study the computational complexity of problems related to the cost of stability, with a focus on weighted voting games.
Publisher: Springer Science and Business Media LLC
Date: 21-07-2007
Publisher: Rocky Mountain Mathematics Consortium
Date: 04-2007
Publisher: The Open Journal
Date: 09-06-2020
DOI: 10.21105/JOSS.01835
Publisher: Springer Science and Business Media LLC
Date: 20-12-2012
Publisher: Wiley
Date: 23-07-2004
Publisher: Cambridge University Press (CUP)
Date: 2000
DOI: 10.1017/S0305004199004028
Abstract: The McLaughlin sporadic simple group McL is the flag-transitive automorphism group of a Petersen-type geometry [Gscr ] = [Gscr ](McL) with the diagram diagram here where the edge in the middle indicates the geometry of vertices and edges of the Petersen graph. The elements corresponding to the nodes from the left to the right on the diagram P 3 3 are called points, lines, triangles and planes, respectively. The residue in [Gscr ] of a point is the P 3 -geometry [Gscr ](Mat 22 ) of the Mathieu group of degree 22 and the residue of a plane is the P 3 -geometry [Gscr ](Alt 7 ) of the alternating group of degree 7. The geometries [Gscr ](Mat 22 ) and [Gscr ](Alt 7 ) possess 3-fold covers [Gscr ](3Mat 22 ) and [Gscr ](3Alt 7 ) which are known to be universal. In this paper we show that [Gscr ] is simply connected and construct a geometry [Gscr ]˜ which possesses a 2-covering onto [Gscr ]. The automorphism group of [Gscr ]˜ is of the form 3 23 McL the residues of a point and a plane are isomorphic to [Gscr ](3Mat 22 ) and [Gscr ](3Alt 7 ), respectively. Moreover, we reduce the classification problem of all flag-transitive P m n -geometries with n , m [ges ] 3 to the calculation of the universal cover of [Gscr ]˜.
Publisher: Elsevier BV
Date: 02-1997
Publisher: Elsevier BV
Date: 11-1996
Publisher: Elsevier BV
Date: 11-1991
Publisher: Springer Science and Business Media LLC
Date: 10-08-2016
Publisher: Springer Science and Business Media LLC
Date: 05-1993
DOI: 10.1007/BF01264914
Publisher: Springer Science and Business Media LLC
Date: 03-02-2020
DOI: 10.1038/S41592-019-0686-2
Abstract: SciPy is an open-source scientific computing library for the Python programming language. Since its initial release in 2001, SciPy has become a de facto standard for leveraging scientific algorithms in Python, with over 600 unique code contributors, thousands of dependent packages, over 100,000 dependent repositories and millions of downloads per year. In this work, we provide an overview of the capabilities and development practices of SciPy 1.0 and highlight some recent technical developments.
Publisher: American Mathematical Society (AMS)
Date: 14-10-2021
DOI: 10.1090/ERT/587
Abstract: We show that any irreducible representation ρ \\rho of a finite group G G of exponent n n , realisable over R \\mathbb {R} , is realisable over the field E ≔ Q ( ζ n ) ∩ R E≔\\mathbb {Q}(\\zeta _n)\\cap \\mathbb {R} of real cyclotomic numbers of order n n , and describe an algorithmic procedure transforming a realisation of ρ \\rho over Q ( ζ n ) \\mathbb {Q}(\\zeta _n) to one over E E .
Publisher: Springer Science and Business Media LLC
Date: 25-01-2017
Publisher: Elsevier BV
Date: 03-2006
Publisher: American Mathematical Society (AMS)
Date: 1995
DOI: 10.1090/S0002-9939-1995-1307498-3
Abstract: Let G be a group acting on a set Ω \Omega and k a non-negative integer. A subset (finite or infinite) A ⊆ Ω A \subseteq \Omega is called k -quasi-invariant if | A g ∖ A | ≤ k |{A^g}\backslash A| \leq k for every g ∈ G g \in G . It is shown that if A is k -quasi-invariant for k ≥ 1 k \geq 1 , then there exists an invariant subset Γ ⊆ Ω \Gamma \subseteq \Omega such that | A △ Γ | 2 e k ⌈ ( ln 2 k ) ⌉ |A\vartriangle \Gamma | 2ek\left \lceil {(\ln 2k)} \right \rceil . Information about G -orbit intersections with A is obtained. In particular, the number m of G -orbits which have non-empty intersection with A , but are not contained in A , is at most 2 k − 1 2k - 1 . Certain other bounds on | A △ Γ | |A\vartriangle \Gamma | , in terms of both m and k , are also obtained.
Publisher: Elsevier BV
Date: 04-1996
Publisher: Springer Science and Business Media LLC
Date: 05-10-2007
Publisher: Springer Science and Business Media LLC
Date: 05-2001
DOI: 10.1007/PL00005804
Publisher: Elsevier BV
Date: 11-1995
Publisher: European Mathematical Society - EMS - Publishing House GmbH
Date: 2010
DOI: 10.4171/JEMS/208
Publisher: Springer Science and Business Media LLC
Date: 05-2011
Publisher: Springer Science and Business Media LLC
Date: 1993
Publisher: Elsevier BV
Date: 05-2017
Publisher: Elsevier BV
Date: 10-1996
Publisher: Society for Industrial and Applied Mathematics
Date: 04-01-2009
Publisher: Springer Science and Business Media LLC
Date: 09-2004
Publisher: Elsevier BV
Date: 07-2001
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2002
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 07-1992
Publisher: Elsevier BV
Date: 05-2009
Publisher: Cambridge University Press
Date: 21-10-1993
Publisher: Springer Science and Business Media LLC
Date: 03-2006
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2013
DOI: 10.1137/120886777
Publisher: Springer Science and Business Media LLC
Date: 22-05-2011
Publisher: Springer Science and Business Media LLC
Date: 12-04-2018
Publisher: Elsevier BV
Date: 10-1994
Publisher: Springer Science and Business Media LLC
Date: 07-2014
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2006
Publisher: Elsevier BV
Date: 09-1993
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2012
DOI: 10.1137/110852206
Publisher: Wiley
Date: 2014
DOI: 10.1112/S1461157014000400
Abstract: Knowing the symmetries of a polyhedron can be very useful for the analysis of its structure as well as for practical polyhedral computations. In this note, we study symmetry groups preserving the linear, projective and combinatorial structure of a polyhedron. In each case we give algorithmic methods to compute the corresponding group and discuss some practical experiences. For practical purposes the linear symmetry group is the most important, as its computation can be directly translated into a graph automorphism problem. We indicate how to compute integral subgroups of the linear symmetry group that are used, for instance, in integer linear programming.
Publisher: Elsevier BV
Date: 2015
Publisher: Springer Berlin Heidelberg
Date: 2010
Publisher: Springer Berlin Heidelberg
Date: 2009
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2008
DOI: 10.1137/070711141
Publisher: Elsevier BV
Date: 03-2003
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland