African University of Science and Technology: Recent submissions

Now showing items 281-300 of 4790

  • Non-reductive automorphism groups, the Loewy filtration and K-stability 

    Codogni, Giulio; Dervan, Ruadhai (l'Institut FourierAnnales de l'Institut Fourier, 2016-03-18)
    We study the K-stability of a polarised variety with non-reductive automorphism group. We associate a canonical filtration of the co-ordinate ring to each variety of this kind, which destabilises the variety in several ...

  • Uniform Stability of Twisted Constant Scalar Curvature Kähler Metrics 

    Dervan, Ruadhai (Oxford University PressInternational Mathematics Research Notices, 2015-10-14)
    We introduce a norm on the space of test configurations, called the minimum norm. We conjecture that uniform K-stability is equivalent to the existence of a constant scalar curvature Kähler metric. This uniformity is ...

  • Alpha invariants and coercivity of the Mabuchi functional on Fano manifolds 

    Dervan, Ruadhai (Université Paul SabatierAnnales de la Faculté des Sciences de Toulouse, 2016)
    We give a criterion for the coercivity of the Mabuchi functional for general Kàhler classes on Fano manifolds in terms of Tian's alpha invariant. This generalises a result of Tian in the anti-canonical case implying the ...

  • A Counter Example to Cercignani’s Conjecture for the d Dimensional Kac Model 

    Einav, Amit (SpringerJournal of Statistical Physics, 2012-08-21)
    Kac’s d dimensional model gives a linear, many particle, binary collision model from which, under suitable conditions, the celebrated Boltzmann equation, in its spatially homogeneous form, arise as a mean field limit. The ...

  • On the Subadditivity of the Entropy on the Sphere 

    Einav, Amit (SpringerThe Journal of Geometric Analysis, 2015-11-17)
    We present a refinement of a known entropic inequality on the sphere, finding suitable conditions under which the uniform probability measure on the sphere behaves asymptomatically like the Gaussian measure on Rᴺ with ...

  • Chaos and Entropic Chaos in Kac's Model Without High Moments 

    Carrapatoso, Kleber; Einav, Amit (Institute of Mathematical StatisticsElectronic Journal of Probability, 2013-08-27)
    In this paper we present a new local Lévy Central Limit Theorem, showing convergence to stable states that are not necessarily the Gaussian, and use it to find new and intuitive entropically chaotic families with underlying ...

  • On Villani's conjecture concerning entropy production for the Kac Master equation 

    Einav, Amit (America Institute of Mathematical SciencesKinetic and Related Models, 2011-06-01)
    In this paper we take an idea presented in recent paper by Carlen, Carvalho, Le Roux, Loss, and Villani ([3]) and push it one step forward to find an exact estimation on the entropy production. The new estimation essentially ...

  • Sharp trace inequalities for fractional Laplacians 

    Einav, Amit; Loss, Michael (American Mathematical SocietyProceedings of the American Mathematical Society, 2012-04-05)
    The sharp trace inequality of José Escobar is extended to traces for the fractional Laplacian on Rⁿ and a complete characterization of cases of equality is discussed. The proof proceeds via Fourier transform and uses Lieb’s ...

  • Deformations of Cayley submanifolds 

    Ohst, Matthias (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsTrinity College, 2016-03-01)
    Cayley submanifolds of R^8 were introduced by Harvey and Lawson as an instance of calibrated submanifolds, extending the volume-minimising properties of complex submanifolds in Kähler manifolds. More generally, Cayley ...

  • Level-raising and symmetric power functoriality, III 

    Clozel, Laurent; Thorne, Jack Arfon (Duke University PressDuke Mathematical Journal, 2016-12-09)
    The simplest case of the Langlands functoriality principle asserts the existence of the symmetric powers Symn of a cuspidal representation of GL.2/ over the adèles of F , where F is a number field. In 1978, Gelbart and ...

  • A 2-adic automorphy lifting theorem for unitary groups over CM fields 

    Thorne, Jack Arfon (SpringerMathematische Zeitschrift, 2016)
    We prove a ‘minimal’ type automorphy lifting theorem for 2-adic Galois representations of unitary type, over imaginary CM fields. We use this to improve an automorphy lifting theorem of Kisin for GL_2.

  • Harmonic Discs of Solutions to the Complex Homogeneous Monge-Ampere Equation 

    Ross, Julius Andrew; Nystrom, David Witt (SpringerPublications mathématiques de l'IHÉS, 2015-05-30)
    We study regularity properties of solutions to the Dirichlet problem for the complex Homogeneous Monge-Ampere equation. We show that for certain boundary data on P^1 the solution Φ to this Dirichlet problem is connected ...

  • Polynomials and models of type theory 

    von Glehn, Tamara (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsMagdalene College, 2015-06-30)
    This thesis studies the structure of categories of polynomials, the diagrams that represent polynomial functors. Specifically, we construct new models of intensional dependent type theory based on these categories. Firstly, ...

  • Variation of Gieseker moduli spaces via quiver GIT 

    Greb, Daniel; Ross, Julius Andrew; Toma, Matei (Mathematical Sciences PublishersGeometry & Topology, 2016)
    We introduce a notion of stability for sheaves with respect to several polarisations that generalises the usual notion of Gieseker-stability. We prove, under a boundedness assumption, which we show to hold on threefolds ...

  • Potential automorphy and the Leopoldt conjecture 

    Khare, Chandrashekhar; Thorne, Jack Arfon (Johns Hopkins University PressAmerican Journal of Mathematics, 2017-10-01)
    We study in this paper Hida's p-adic Hecke algebra for GL_n over a CM field F. Hida has made a conjecture about the dimension of these Hecke algebras, which he calls the non-abelian Leopoldt conjecture, and shown that his ...

  • Quantifying separability in virtually special groups 

    Hagen, Mark Fearghus; Patel, Priyam (Mathematical Society PublishingPacific Journal of Mathematics, 2016)
    We give a new, effective proof of the separability of cubically convex-cocompact subgroups of special groups. As a consequence, we show that if G is a virtually compact special hyperbolic group, and Q ≤ G is a K-quasiconvex ...

  • Cubulating hyperbolic free-by-cyclic groups: the irreducible case 

    Hagen, Mark Fearghus; Wise, Daniel T (Duke University PressDuke Mathematical Journal, 2016)
    Let V be a fi nite graph and let ∅ : V → V be an irreducible train track map whose mapping torus has word-hyperbolic fundamental group G. Then G acts freely and cocompactly on a CAT(0) cube complex. Hence, if F is a ...

  • The 1-2 model 

    Grimmett, Geoffrey Richard; Li, Zhongyang (American Mathematical SocietyIn the Tradition of Ahlfors–Bers, VII, 2017)
    The current paper is a short review of rigorous results for the 1-2 model. The 1-2 model on the hexagonal lattice is a model of statistical mechanics in which each vertex is constrained to have degree either 1 or 2. It was ...


  • Detecting and Localizing Differences in Functional Time Series Dynamics: A Case Study in Molecular Biophysics 

    Tavakoli, Shahin; Panaretos, Victor M (Taylor & FrancisJournal of the American Statistical Association, 2016-03-22)
    Motivated by the problem of inferring the molecular dynamics of DNA in solution, and linking them with its base-pair composition, we consider the problem of comparing the dynamics of functional time series (FTS), and of ...