DSpace community: Centre de Recerca Matemàtica

Convolution inequalities in Lorentz spaces

Sat, 29 Mar 2008 22:58:59 GMT

title: Convolution inequalities in Lorentz spaces authors: Nursultanov, Erlan; Tikhonov, Sergey Yu.
abstract: In this paper we study boundedness of the convolution operator in different Lorentz spaces. In particular, we obtain the limit case of the Young-O'Neil inequality in the classical Lorentz spaces. We also investigate the convolution operator in the weighted Lorentz spaces. Finally, norm inequalities for the potential operator are presented.

Horospheres in hyperbolic geometry

Sat, 29 Mar 2008 22:58:59 GMT

title: Horospheres in hyperbolic geometry authors: Gallego Gómez, Eduardo; Reventós i Tarrida, Agustí; Solanes Farrés, Gil; Teufel, E.
abstract: In this paper we investigate the role of horospheres in Integral Geometry and Differential Geometry. In particular we study envelopes of families of horocycles by means of “support maps”. We define invariant “linear combinations” of support maps or curves. Finally we obtain Gauss-Bonnet type formulas and Chern-Lashof type inequalities.

Proper actions, fixed-point algebras and naturality in nonabelian duality

Sat, 29 Mar 2008 22:58:59 GMT

title: Proper actions, fixed-point algebras and naturality in nonabelian duality authors: Kaliszewski, S.; Quigg, John; Raeburn, Iain
abstract: "Vegeu el resum a l'incici del document del fitxer adjunt."

Net spaces and boundedness of integral operators

Sat, 29 Mar 2008 22:58:59 GMT

title: Net spaces and boundedness of integral operators authors: Nursultanov, Erlan; Tikhonov, Sergey Yu.
abstract: In this paper we introduce new functional spaces which we call the net spaces. Using their properties, the necessary and sufficient conditions for the integral operators to be of strong or weak-type are obtained. The estimates of the norm of the convolution operator in weighted Lebesgue spaces are presented.