Results 11 to 20 of about 107 (95)
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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On a class of globally analytic hypoelliptic sums of squares
Journal of Differential Equations, 2022 We consider sums of squares operators globally defined on the torus. We show that if some assumptions are satisfied the operators are globally analytic hypoelliptic. The purpose of the assumptions is to rule out the existence of a Hamilton leaf on the characteristic variety lying along the fiber of the cotangent bundle, i.e.
Antonio Bove, Gregorio Chinni
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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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A Necessary Condition For Analytic Hypoellipticity [PDF]
Mathematical Research Letters, 1994 The author continues his careful study of the analytic hypoellipticity of Hörmander's Laplacians. He considers here two real linearly independent analytic vector fields \(X_1\), \(X_2\) defined in an open set \(\Omega\subset \mathbb{R}^3\) such that the Hörmander's condition is satisfied (that is that the Lie algebra generated by \(X_1\) and \(X_2 ...
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Analytic hypoellipticity for sums of squares and the Treves conjecture [PDF]
Journal of Functional Analysis, 2018 We are concerned with the problem of real analytic regularity of the solutions of sums of squares with real analytic coefficients. Treves conjecture states that an operator of this type is analytic hypoelliptic if and only if all the strata in the Poisson-Treves stratification are symplectic.
Albano, Paolo +2 more
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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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Non-analytic hypoellipticity in the presence of symplecticity [PDF]
Proceedings of the American Mathematical Society, 1998 Here we construct non-analytic solutions to a class of hypoelliptic operators with symplectic characteristic set and in the form of a sum of squares of real analytic vector fields.
Hanges, Nicholas, Himonas, A. Alexandrou
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Analytic Hypoellipticity for Generalized Baouendi-Goulaouic Operators
Journal of Functional Analysis, 1994 The authors consider the linear differential operator \[ P= \biggl( {\partial\over {\partial x}} \biggr)^ 2+ \biggl( a(x) {\partial\over {\partial y}} \biggr)^ 2+ \biggl( {\partial \over {\partial t}} \biggr)^ 2, \] \(a(x)\) being real-analytic, real-valued function near 0 and prove that \(P\) is analytic hypoelliptic at the origin in \(\mathbb{R}^ 3\)
Hanges, Nicholas, Himonas, A. Alexandrou
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