Extension of the best approximation operator in Orlicz spaces.
Extension of vector-valued holomorphic and harmonic functions
We present a unified approach to the study of extensions of vector-valued holomorphic or harmonic functions based on the existence of weak or weak*-holomorphic or harmonic extensions. Several recent results due to Arendt, Nikolski, Bierstedt, Holtmanns and Grosse-Erdmann are extended. An open problem by Grosse-Erdmann is solved in the negative. Using the extension results we prove existence of Wolff type representations for the duals of certain function spaces.
Extension operators for analytic functions defined on certain closed subvarieties of a Stein space
Extension operators on balls and on spaces of finite sets
We study extension operators between spaces of continuous functions on the spaces of subsets of X of cardinality at most n. As an application, we show that if is the unit ball of a nonseparable Hilbert space H equipped with the weak topology, then, for any 0 < λ < μ, there is no extension operator .
Extension via interpolation
We suggest a modification of the Pawłucki and Pleśniak method to construct a continuous linear extension operator by means of interpolation polynomials. As an illustration we present explicitly the extension operator for the space of Whitney functions given on the Cantor ternary set.
Extensions and Selections in Subspaces of C(K).
Extensions by mollifiers in Basov spaces
Extensions de jets dans des intersections de classes non quasi-analytiques
In [3], J. Chaumat and A.-M. Chollet prove, among other things, a Whitney extension theorem, for jets on a compact subset E of ℝⁿ, in the case of intersections of non-quasi-analytic classes with moderate growth and a Łojasiewicz theorem in the regular situation. These intersections are included in the intersection of Gevrey classes. Here we prove an extension theorem in the case of more general intersections such that every -Whitney jet belongs to one of them. We also prove a linear extension theorem...
Extensions from the Sobolev spaces satisfying prescribed Dirichlet boundary conditions
Extensions from into (where ) are constructed in such a way that extended functions satisfy prescribed boundary conditions on the boundary of . The corresponding extension operator is linear and bounded.
Extensions of compact continuous maps into decomposable sets
Extensions of Hardy inequality.
Extensions of operators and the Dirichlet problem in potential theory
Extensions of the representation theorems of Riesz and Fréchet
We present two types of representation theorems: one for linear continuous operators on space of Banach valued regulated functions of several real variables and the other for bilinear continuous operators on cartesian products of spaces of regulated functions of a real variable taking values on Banach spaces. We use generalizations of the notions of functions of bounded variation in the sense of Vitali and Fréchet and the Riemann-Stieltjes-Dushnik or interior integral. A few applications using geometry...
Extensions of weak type multipliers
We prove that if and has compact support then Λ is a weak summability kernel for 1 < p < ∞, where is the space of multipliers of .
Extraction of a “good” subsequence from a bounded sequence of integrable functions.
Extrapolation functors on a family of scales generated by the real interpolation method.
Extrapolation of Sobolev imbeddings.
We survey recent results on limiting imbeddings [sic] of Sobolev spaces, particularly, those concerning weakening of assumptions on integrability of derivatives, considering spaces with dominating mixed derivatives and the case of weighted spaces.
Extrapolation theory for the real interpolation method.
We develop an abstract extrapolation theory for the real interpolation method that covers and improves the most recent versions of the celebrated theorems of Yano and Zygmund. As a consequence of our method, we give new endpoint estimates of the embedding Sobolev theorem for an arbitrary domain Omega.
Extrapolatory description for the Lorentz and Marcinkiewicz spaces “close" to .
Extremal functions for the anisotropic Sobolev inequalities