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Heat kernel and semigroup estimates for sublaplacians with drift on Lie groups.

Nick Dungey (2005)

Publicacions Matemàtiques

Let G be a Lie group. The main new result of this paper is an estimate in L2 (G) for the Davies perturbation of the semigroup generated by a centered sublaplacian H on G. When G is amenable, such estimates hold only for sublaplacians which are centered. Our semigroup estimate enables us to give new proofs of Gaussian heat kernel estimates established by Varopoulos on amenable Lie groups and by Alexopoulos on Lie groups of polynomial growth.

Heat kernel estimates for a class of higher order operators on Lie groups

Nick Dungey (2005)

Studia Mathematica

Let G be a Lie group of polynomial volume growth. Consider a differential operator H of order 2m on G which is a sum of even powers of a generating list A , . . . , A d ' of right invariant vector fields. When G is solvable, we obtain an algebraic condition on the list A , . . . , A d ' which is sufficient to ensure that the semigroup kernel of H satisfies global Gaussian estimates for all times. For G not necessarily solvable, we state an analytic condition on the list which is necessary and sufficient for global Gaussian estimates....

Heat kernels and Riesz transforms on nilpotent Lie groups

A. ter Elst, Derek Robinson, Adam Sikora (1998)

Colloquium Mathematicae

We consider pure mth order subcoercive operators with complex coefficients acting on a connected nilpotent Lie group. We derive Gaussian bounds with the correct small time singularity and the optimal large time asymptotic behaviour on the heat kernel and all its derivatives, both right and left. Further we prove that the Riesz transforms of all orders are bounded on the Lp -spaces with p ∈ (1, ∞). Finally, for second-order operators with real coefficients we derive matching Gaussian lower bounds...

High order regularity for subelliptic operators on Lie groups of polynomial growth.

Nick Dungey (2005)

Revista Matemática Iberoamericana

Let G be a Lie group of polynomial volume growth, with Lie algebra g. Consider a second-order, right-invariant, subelliptic differential operator H on G, and the associated semigroup St = e-tH. We identify an ideal n' of g such that H satisfies global regularity estimates for spatial derivatives of all orders, when the derivatives are taken in the direction of n'. The regularity is expressed as L2 estimates for derivatives of the semigroup, and as Gaussian bounds for derivatives of the heat kernel....

Hilbert-Smith Conjecture for K - Quasiconformal Groups

Gong, Jianhua (2010)

Fractional Calculus and Applied Analysis

MSC 2010: 30C60A more general version of Hilbert's fifth problem, called the Hilbert-Smith conjecture, asserts that among all locally compact topological groups only Lie groups can act effectively on finite-dimensional manifolds. We give a solution of the Hilbert-Smith Conjecture for K - quasiconformal groups acting on domains in the extended n - dimensional Euclidean space.

Hölder a priori estimates for second order tangential operators on CR manifolds

Annamaria Montanari (2003)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

On a real hypersurface M in n + 1 of class C 2 , α we consider a local CR structure by choosing n complex vector fields W j in the complex tangent space. Their real and imaginary parts span a 2 n -dimensional subspace of the real tangent space, which has dimension 2 n + 1 . If the Levi matrix of M is different from zero at every point, then we can generate the missing direction. Under this assumption we prove interior a priori estimates of Schauder type for solutions of a class of second order partial differential equations...

Holomorphic actions, Kummer examples, and Zimmer program

Serge Cantat, Abdelghani Zeghib (2012)

Annales scientifiques de l'École Normale Supérieure

We classify compact Kähler manifolds M of dimension n 3 on which acts a lattice of an almost simple real Lie group of rank n - 1 . This provides a new line in the so-called Zimmer program, and characterizes certain complex tori as compact Kähler manifolds with large automorphisms groups.

Holomorphic automorphisms and collective compactness in J*-algebras of operator

José Isidro (2007)

Open Mathematics

Let G be the Banach-Lie group of all holomorphic automorphisms of the open unit ball B 𝔄 in a J*-algebra 𝔄 of operators. Let 𝔉 be the family of all collectively compact subsets W contained in B 𝔄 . We show that the subgroup F ⊂ G of all those g ∈ G that preserve the family 𝔉 is a closed Lie subgroup of G and characterize its Banach-Lie algebra. We make a detailed study of F when 𝔄 is a Cartan factor.

Currently displaying 21 – 40 of 70