1,721,031 research outputs found
A twisted Fréchet space with basis
No full textIn this note we show that the twisted Fréchet and (LB)-spaces constructed by the second author in [6, § 1] and which were known not to have unconditional bases may, however, have a basis. © 1988 Springer-Verlag
Analyticity of the Cox–Ingersoll–Ross semigroup
No full textWe study the analyticity of the Cox–Ingersoll–Ross semigroup generated by Aru=ν2xu′′+γu′+βxu′-rxu,in spaces of continuous functions on [ 0 , + ∞) and we provide the full description of the domain of the generator
Degenerate operators on the half-line
Full text linkWe study elliptic and parabolic problems governed by the singular elliptic operators yα(Dyy+cyDy)-V(y),α∈Rin R+, where V is a potential having nonnegative real part
Erratum: Dirichlet boundary conditions for elliptic operators with unbounded drift (Proceedings of the American Mathematical Society (2005) 133:9 (2625-2635))
No full textGlobal properties of invariant measures
No full textWe study global regularity properties of invariant measures associated with second order differential operators in . Under suitable conditions, we prove global boundedness of the density, Sobolev regularity, a Harnack inequality and pointwise upper and lower bounds.
Many local regularity properties are known for invariant measures, even under very weak conditions on the coefficients, see e.g. [MR1876411 (2002m:60117)]. On the other hand,
to our knowledge the only available results dealing with global regularity are [MR1351647 (96m:28015)] and [MR1391637 (98d:60120)], which have been the starting point of our investigation.
The proofs relies upon Lyapunov functions and Moser's iteration techniques
L^p estimates for the Caffarelli-Silvestre extension operators
No full textWe study elliptic and parabolic problems governed by the singular elliptic operators L= x+Dyy+ c yDy − b y2 in the half-space RN+1 + ={(x, y) :x∈RN, y>0}
The Ornstein-Uhlenbeck semigroup in finite dimension
No full textWe gather the main known results concerning the non-degenerate Ornstein-Uhlenbeck semigroup in finite dimension. This article is part of the theme issue 'Semigroup applications everywhere'
Kernel Estimates for Schroedinger Operators
No full textWe prove short time estimates for the heat kernel of Schrödinger operators with unbounded potential in . More precisely, if we denote by the heat kernel of the Schrödinger operator , then we prove upper bounds like for a large class of potentials tending to as , under the main assumption that satisfies as and , where g is a convex function growing faster than linearly. The behaviour of c(t) near 0 is also shown to be precise. Similar bounds are also proved for the derivatives of p. Our analysis provides a family of such estimates e.g. for for every
The Ornstein-Uhlenbeck semigroup in finite dimension
No full textWe gather the main known results concerning the non-degenerate Ornstein-Uhlenbeck semigroup in finite dimension. This article is part of the theme issue 'Semigroup applications everywhere'
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