Results 61 to 70 of about 425 (156)
On a class of globally analytic hypoelliptic sums of squares [PDF]
, 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.
Gregorio Chinni, Antonio Bove
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On curvature bounds in Lorentzian length spaces
Journal of the London Mathematical Society, Volume 110, Issue 2, August 2024.Abstract We introduce several new notions of (sectional) curvature bounds for Lorentzian pre‐length spaces: On the one hand, we provide convexity/concavity conditions for the (modified) time separation function, and, on the other hand, we study four‐point conditions, which are suitable also for the non‐intrinsic setting. Via these concepts, we are able
Tobias Beran +2 more
wiley +1 more source
A parametrix for step-two hypoelliptic diffusion equations [PDF]
, 1986 In this paper I construct a parametrix for the hypoelliptic diffusion equations ( ∂ / ∂ t − L ) u = 0 (\partial /\partial t - L)u = 0 , where
Thomas Taylor
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On the properties of the symbols of one class of hypoelliptic equations
Sibirskii zhurnal industrial'noi matematiki, 2019 We consider regular hypoelliptic operators and study some properties of completely regular polyhedra. Basing on the obtained properties, we find an upper bound for the functional dimension of the solution spaces of hypoelliptic equations.
openaire +3 more sources
The Metivier inequality and ultradifferentiable hypoellipticity
Mathematische Nachrichten, Volume 297, Issue 7, Page 2517-2531, July 2024.Abstract In 1980, Métivier characterized the analytic (and Gevrey) hypoellipticity of L2$L^2$‐solvable partial linear differential operators by a priori estimates. In this note, we extend this characterization to ultradifferentiable hypoellipticity with respect to Denjoy–Carleman classes given by suitable weight sequences. We also discuss the case when
Paulo D. Cordaro, Stefan Fürdös
wiley +1 more source
Harnack inequality for hypoelliptic ultraparabolic equations with a singular lower order term [PDF]
, 2005 We prove a Harnack inequality for the positive solutions of ultraparabolic equations of the type L u + V u= 0, where L is a linear second order hypoelliptic operator and V belongs to a class of functions of Stummel-Kato type.
Polidoro, Sergio +1 more
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Harnack inequalities for hypoelliptic evolution operators: geometric issues and applications
Bruno Pini Mathematical Analysis Seminar, 2012 We consider linear second order Partial Differential Equations in the form of "sum of squares of Hörmander vector fields plus a drift term" on a given domain.
Sergio Polidoro
doaj
Relation between Growth and Regularity of Solutions of Hypoelliptic Equations [PDF]
Proceedings of the American Mathematical Society, 1988 For a class of linear partial differential equations with variable coefficients, it is shown that the Gevrey regularity of solutions depends on their growth at infinity.
M. Shafii-Mousavi, Z. Zielezny
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Bulletin of the London Mathematical Society, Volume 56, Issue 3, Page 981-1003, March 2024.Abstract We study the linear relaxation Boltzmann equation on the torus with a spatially varying jump rate which can be zero on large sections of the domain. In Bernard and Salvarani (Arch. Ration. Mech. Anal. 208 (2013), no. 3, 977–984), Bernard and Salvarani showed that this equation converges exponentially fast to equilibrium if and only if the jump
Josephine Evans, Iván Moyano
wiley +1 more source
Harnack inequality for hypoelliptic ultraparabolic equations with a singular lower order term [PDF]
, 2008 We prove a Harnack inequality for the positive solutions of ultraparabolic equations of the type L u + V u = 0;where L is a linear second order hypoelliptic differential operator and V belongs to a class of functions of Stummel-Kato type.
Maria Alessandra Ragusa +3 more
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