Results 21 to 30 of about 3,789 (142)

FRACTIONAL ORDER KINETIC EQUATIONS AND HYPOELLIPTICITY [PDF]

open access: yesAnalysis and Applications, 2012
We give simple proofs of hypoelliptic estimates for some models of kinetic equations with a fractional order diffusion part. The proofs are based on energy estimates together with the previous ideas of Bouchut and Perthame.
openaire   +2 more sources

Global Hypoellipticity for Strongly Invariant Operators

open access: yes, 2020
In this note, by analyzing the behavior at infinity of the matrix symbol of an invariant operator $P$ with respect to a fixed elliptic operator, we obtain a necessary and sufficient condition to guarantee that $P$ is globally hypoelliptic.
de Moraes, Wagner Augusto Almeida   +1 more
core   +1 more source

Hypoelliptic convolution equations in the space 𝒦’ₑ [PDF]

open access: yesTransactions of the American Mathematical Society, 1986
We consider convolution equations in the space K e ′ \mathcal {K}_e’ of distributions which "grow" no faster than exp ⁡ ( e k | x |
openaire   +1 more source

Global $L^{p}$ estimates for degenerate Ornstein-Uhlenbeck operators with variable coefficients [PDF]

open access: yes, 2012
We consider a class of degenerate Ornstein-Uhlenbeck operators in $\mathbb{R}^{N}$, of the kind [\mathcal{A}\equiv\sum_{i,j=1}^{p_{0}}a_{ij}(x) \partial_{x_{i}x_{j}}^{2}+\sum_{i,j=1}^{N}b_{ij}x_{i}\partial_{x_{j}}%] where $(a_{ij})$ is symmetric ...
  +13 more
core   +3 more sources

Theory of B(X)‐Module: Algebraic Module Structure of Generally Unbounded Infinitesimal Generators

open access: yesAdvances 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
wiley   +1 more source

The sharp maximal function approach to $L^{p}$ estimates for operators structured on H\"{o}rmander's vector fields [PDF]

open access: yes, 2015
We consider a nonvariational degenerate elliptic operator structured on a system of left invariant, 1-homogeneous, H\"ormander's vector fields on a Carnot group in $R^{n}$, where the matrix of coefficients is symmetric, uniformly positive on a bounded ...
Bramanti, Marco, Toschi, Marisa
core   +2 more sources

Fundamental solutions in the Colombeau framework: applications to solvability and regularity theory [PDF]

open access: yes, 2007
In this article we introduce the notion of fundamental solution in the Colombeau context as an element of the dual $\LL(\Gc(\R^n),\wt{\C})$. After having proved the existence of a fundamental solution for a large class of partial differential operators ...
Garetto, Claudia
core   +3 more sources

Hypoelliptic regularity in kinetic equations

open access: yesJournal de Mathématiques Pures et Appliquées, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +1 more source

Null-controllability of hypoelliptic quadratic differential equations [PDF]

open access: yesJournal de l’École polytechnique — Mathématiques, 2017
We study the null-controllability of parabolic equations associated with a general class of hypoelliptic quadratic differential operators. Quadratic differential operators are operators defined in the Weyl quantization by complex-valued quadratic symbols.
Beauchard, Karine, Pravda-Starov, Karel
openaire   +5 more sources

Global Gevrey hypoellipticity on the torus for a class of systems of complex vector fields

open access: yes, 2018
Let $L_j = \partial_{t_j} + (a_j+ib_j)(t_j) \partial_x, \, j = 1, \dots, n,$ be a system of vector fields defined on the torus $\mathbb{T}_t^{n}\times\mathbb{T}_x^1$, where the coefficients $a_j$ and $b_j$ are real-valued functions belonging to the ...
de Medeira, Cleber   +2 more
core   +1 more source

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