Browsing Department of Pure Mathematics and Mathematical Statistics (DPMMS) by Title

Now showing items 189-208 of 248

  • Small-time fluctuations for sub-Riemannian diffusion loops 

    Habermann, Karen
    We study the small-time fluctuations for diffusion processes which are conditioned by their initial and final positions, under the assumptions that the diffusivity has a sub-Riemannian structure and that the drift vector ...

  • SMOOTH PRINCIPAL COMPONENT ANALYSIS OVER TWO-DIMENSIONAL MANIFOLDS WITH AN APPLICATION TO NEUROIMAGING 

    Lila, Eardi; Aston, John Alexander; Sangalli, Laura M (Institute of Mathematical StatisticsThe Annals of Applied Statistics, 2016-01-05)
    Motivated by the analysis of high-dimensional neuroimaging signals located over the cortical surface, we introduce a novel Principal Component Analysis technique that can handle functional data located over a two-dimensional ...


  • Spectral gap in the group of affine transformations over prime fields 

    Lindenstrauss, E; Varju, Peter Pal (University of ToulouseAnnales de la Faculte des Sciences de Toulousehttp://afst.cedram.org/item?id=AFST_2016_6_25_5_969_0, 2016-11-01)
    We study random walks on the groups $\Bbb F^d_p \rtimes$ SL$_d$($\Bbb F_p$). We estimate the spectral gap in terms of the spectral gap of the projection to the linear part SL$_d$($\Bbb F_p$). This problem is motivated by ...

  • Spectral methods and computational trade-offs in high-dimensional statistical inference 

    Wang, Tengyao (Department of Pure Mathematics and Mathematical Statistics, University of CambridgeUniversity of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsFaculty of MathematicsSt John's College, 2016-10-04)
    Spectral methods have become increasingly popular in designing fast algorithms for modern highdimensional datasets. This thesis looks at several problems in which spectral methods play a central role. In some cases, we ...

  • Stability and bifurcation for the Kuramoto model 

    Dietert, Helge (ElsevierJournal de Mathématiques Pures et Appliquées, 2015-11-11)
    We study the mean-field limit of the Kuramoto model of globally coupled oscillators. By studying the evolution in Fourier space and understanding the domain of dependence, we show a global stability result. Moreover, we ...

  • Stability of charged rotating black holes for linear scalar perturbations 

    Civin, Damon (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsCambridge Centre for Analysis, 2015-03-03)
    In this thesis, the stability of the family of subextremal Kerr-Newman space- times is studied in the case of linear scalar perturbations. That is, nondegenerate energy bounds (NEB) and integrated local energy decay ...

  • Stackings and the W-cycles conjecture 

    Louder, L; Wilton, Henry John
    We prove Wise’s W-cycles conjecture: Consider a compact graph Γ′ immersing into another graph Γ. For any immersed cycle Λ : S¹ → Γ, we consider the map Λ′ from the circular components S of the pullback to Γ′. Unless Λ′ is ...

  • Statistical and computational trade-offs in estimation of sparse principal components 

    Wang, Tengyao; Berthet, Quentin; Samworth, Richard John (Institute of Mathematical StatisticsAnnals of Statistics, 2016)
    In recent years, Sparse Principal Component Analysis has emerged as an extremely popular dimension reduction technique for highdimensional data. The theoretical challenge, in the simplest case, is to estimate the leading ...

  • Statistical issues in Mendelian randomization: use of genetic instrumental variables for assessing causal associations 

    Burgess, Stephen (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsMRC Biostatistics Unit, 2012-03-06)
    Mendelian randomization is an epidemiological method for using genetic variation to estimate the causal effect of the change in a modifiable phenotype on an outcome from observational data. A genetic variant satisfying ...

  • Sufficientness postulates for Gibbs-type priors and hierarchical generalizations 

    Bacallado de Lara, Sergio Andres; Battiston, M; Favaro, S; Trippa, L
    A fundamental problem in Bayesian nonparametrics consists of selecting a prior distribution by assuming that the corresponding predictive probabilities obey certain properties. An early discussion of such a problem, although ...

  • Symmetric structures in Banach spaces 

    Gowers, William T. (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsTrinity College, 1990-02-20)

  • Symmetry in monotone Lagrangian Floer theory 

    Smith, Jack Edward (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsTrinity College, 2017-10-01)
    In this thesis we study the self-Floer theory of a monotone Lagrangian submanifold $L$ of a closed symplectic manifold $X$ in the presence of various kinds of symmetry. First we consider the group $\mathrm{Symp}(X, L)$ ...

  • Tautological rings for high-dimensional manifolds 

    Galatius, S; Grigoriev, I; Randal-Williams, Oscar (Cambridge University PressCompositio Mathematica, 2017-04)
    We study tautological rings for high-dimensional manifolds, that is, for each smooth manifold $M$ the ring $R^*$($M$) of those characteristic classes of smooth fibre bundles with fibre $M$ which is generated by generalised ...

  • Teichmüller spaces and bounded symmetric domains do not mix isometrically 

    Antonakoudis, Stergios (SpringerGeometric and Functional Analysis, 2017-06-01)
    This paper shows that, in dimensions two or more, there are no holomorphic isometries between Teichüller spaces and bounded symmetric domains in their intrinsic Kobayashi metric.

  • Tests for separability in nonparametric covariance operators of random surfaces 

    Aston, John Alexander; Pigoli, Davide; Tavakoli, Shahin (Institute of Mathematical StatisticsAnnals of Statistics, 2016)
    The assumption of separability of the covariance operator for a random image or hypersurface can be of substantial use in applications, especially in situations where the accurate estimation of the full covariance structure ...

  • $\textit{K}$-Theory of Fermat Curves 

    Cain, Christopher (Department of Pure Mathematics and Mathematical Statistics, University of CambridgeUniversity of CambridgeChurchill College, 2017-01-10)
    I investigate the $K_2$ groups of the quotients of Fermat curves given in projective coordinates by the equation $F_n:X^n+Y^n=Z^n$. On any quotient where the number of known elements is equal to the rank predicted by ...

  • 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 ...

  • The augmented base locus of real divisors over arbitrary fields 

    Birkar, Caucher (SpringerMathematische Annalen, 2016-07-08)
    We show that the augmented base locus coincides with the exceptional locus (i.e., null locus) for any nef $\Bbb R$-Cartier divisor on any scheme projective over a field (of any characteristic). Next we prove a semi-ampleness ...

  • The Calderón problem for connections 

    Cekić, Mihajlo (University of CambridgeDepartment of Pure Mathematics and Mathematical StatisticsTrinity College, 2017-10-03)
    This thesis is concerned with the inverse problem of determining a unitary connection $A$ on a Hermitian vector bundle $E$ of rank $m$ over a compact Riemannian manifold $(M, g)$ from the Dirichlet-to-Neumann (DN) ...