Results 11 to 20 of about 125 (119)
Enhanced dissipation and Taylor dispersion in higher‐dimensional parallel shear flows
Journal of the London Mathematical Society, Volume 108, Issue 4, Page 1358-1392, October 2023., 2023 Abstract We consider the evolution of a passive scalar advected by a parallel shear flow in an infinite cylinder with bounded cross section, in arbitrary space dimension. The essential parameters of the problem are the molecular diffusivity ν$\nu$, which is assumed to be small, and the wave number k$k$ in the streamwise direction, which can take ...
Michele Coti Zelati, Thierry Gallay
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Time regularity for generalized Mehler semigroups
Mathematische Nachrichten, Volume 295, Issue 11, Page 2223-2245, November 2022., 2022 Abstract We study continuity and Hölder continuity of t↦Ptf$t\mapsto P_tf$, where Pt$P_t$ is a generalized Mehler semigroup in Cb(X)$C_b(X)$, the space of the continuous and bounded functions from a Banach space X to R$\mathbb {R}$, and f∈Cb(X)$f\in C_b(X)$.
Alessandra Lunardi
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Manifold Markov chain Monte Carlo methods for Bayesian inference in diffusion models
Journal of the Royal Statistical Society: Series B (Statistical Methodology), Volume 84, Issue 4, Page 1229-1256, September 2022., 2022 Abstract Bayesian inference for nonlinear diffusions, observed at discrete times, is a challenging task that has prompted the development of a number of algorithms, mainly within the computational statistics community. We propose a new direction, and accompanying methodology—borrowing ideas from statistical physics and computational chemistry—for ...
Matthew M. Graham +2 more
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Analytic hypoellipticity of Keldysh operators
Proceedings of the London Mathematical Society, Volume 123, Issue 5, Page 498-516, November 2021., 2021 Abstract We consider Keldysh‐type operators, P=x1Dx12+a(x)Dx1+Q(x,Dx′), x=(x1,x′) with analytic coefficients, and with Q(x,Dx′) second order, principally real and elliptic in Dx′ for x near zero. We show that if Pu=f, u∈C∞, and f is analytic in a neighbourhood of 0, then u is analytic in a neighbourhood of 0.
Jeffrey Galkowski, Maciej Zworski
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Almost Periodic Functions and Their Applications: A Survey of Results and Perspectives
Journal of Mathematics, Volume 2021, Issue 1, 2021., 2021 The main aim of this survey article is to present several known results about vector‐valued almost periodic functions and their applications. We separately consider almost periodic functions depending on one real variable and almost periodic functions depending on two or more real variables.
Wei-Shih Du +3 more
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Bulletin: Classe des sciences mathematiques et natturalles, 2002 We give a condition of sufficiency for the hypoellipticity of a family of equations with constant coefficients satisfied prescribed power growth rate with respect to ? ? (0, 1). The framework is Colombeau algebra of generalized functions.
Nedeljkov, Marko, Pilipović, Stevan
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Electronic Communications in Probability, 2016 We prove that if the Markov generator of a diffusion process satisfies the two step strong Hörmander condition, the conditioned hypoelliptic bridge satisfies an integral bound and is a continuous semi-martingale.
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Some Remarks on Hypoelliptic Operators which are not Micro-hypoelliptic
Publications of the Research Institute for Mathematical Sciences, 1992 We give an example of hypoelliptic operators which are not micro- hypoelliptic. Non-micro-hypoellipticity of the example arises from the oscillation of the coefficient with a zero of infinite order.
Morimoto, Yoshinori, Morioka, Tatsushi
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On Global Hypoellipticity [PDF]
Communications in Partial Differential Equations, 2012 We consider a first order linear partial differential operator of principal type on a closed connected orientable two-dimensional manifold sending sections of one complex line bundle to sections of another. We prove that the assumption of global hypoellipticity of the operator implies a relation between the degrees of the line bundles and the Euler ...
A. P. Bergamasco, G. A. Mendoza, S. Zani
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Theory of B(X)‐Module: Algebraic Module Structure of Generally Unbounded Infinitesimal Generators
Advances in Mathematical Physics, Volume 2020, Issue 1, 2020., 2020 The concept of logarithmic representation of infinitesimal generators is introduced, and it is applied to clarify the algebraic structure of bounded and unbounded infinitesimal generators. In particular, by means of the logarithmic representation, the bounded components can be extracted from generally unbounded infinitesimal generators.
Yoritaka Iwata, Ricardo Weder
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