Page 1 Next

Displaying 1 – 20 of 24

Showing per page

Parametrization of Riemann-measurable selections for multifunctions of two variables with application to differential inclusions

Giovanni Anello, Paolo Cubiotti (2004)

Annales Polonici Mathematici

We consider a multifunction F : T × X 2 E , where T, X and E are separable metric spaces, with E complete. Assuming that F is jointly measurable in the product and a.e. lower semicontinuous in the second variable, we establish the existence of a selection for F which is measurable with respect to the first variable and a.e. continuous with respect to the second one. Our result is in the spirit of [11], where multifunctions of only one variable are considered.

Partially additive states on orthomodular posets

Josef Tkadlec (1991)

Colloquium Mathematicae

We fix a Boolean subalgebra B of an orthomodular poset P and study the mappings s:P → [0,1] which respect the ordering and the orthocomplementation in P and which are additive on B. We call such functions B-states on P. We first show that every P possesses "enough" two-valued B-states. This improves the main result in [13], where B is the centre of P. Moreover, it allows us to construct a closure-space representation of orthomodular lattices. We do this in the third section. This result may also...

Points fixes et théorèmes ergodiques dans les espaces L¹(E)

Mourad Besbes (1992)

Studia Mathematica

We prove that for each linear contraction T : X → X (∥T∥ ≤ 1), the subspace F = {x ∈ X : Tx = x} of fixed points is 1-complemented, where X is a suitable subspace of L¹(E*) and E* is a separable dual space such that the weak and weak* topologies coincide on the unit sphere. We also prove some related fixed point results.

Pointwise compactness and continuity of the integral.

G. Vera (1996)

Revista Matemática de la Universidad Complutense de Madrid

In this paper we bring together the different known ways of establishing the continuity of the integral over a uniformly integrable set of functions endowed with the topology of pointwise convergence. We use these techniques to study Pettis integrability, as well as compactness in C(K) spaces endowed with the topology of pointwise convergence on a dense subset D in K.

Positive operator bimeasures and a noncommutative generalization

Kari Ylinen (1996)

Studia Mathematica

For C*-algebras A and B and a Hilbert space H, a class of bilinear maps Φ: A× B → L(H), analogous to completely positive linear maps, is studied. A Stinespring type representation theorem is proved, and in case A and B are commutative, the class is shown to coincide with that of positive bilinear maps. As an application, the extendibility of a positive operator bimeasure to a positive operator measure is shown to be equivalent to various conditions involving positive scalar bimeasures, pairs of...

Positive vector measures with given marginals

Surjit Singh Khurana (2006)

Czechoslovak Mathematical Journal

Suppose E is an ordered locally convex space, X 1 and X 2 Hausdorff completely regular spaces and Q a uniformly bounded, convex and closed subset of M t + ( X 1 × X 2 , E ) . For i = 1 , 2 , let μ i M t + ( X i , E ) . Then, under some topological and order conditions on E , necessary and sufficient conditions are established for the existence of an element in Q , having marginals μ 1 and μ 2 .

Projective limits of vector measures.

Fidel José Fernández y Fernández-Arroyo, Pedro Jiménez Guerra (1990)

Revista Matemática de la Universidad Complutense de Madrid

A necessary and sufficient condition for the existence of the projective limit of measures with values in a locally convex space is given. A similar theorem for measures with values in different locally convex spaces (under certain conditions) is given too (in this case, the projective limit is valued in the projective limit of these spaces). Finally, a result about the projective limit of vector measures is stated.

Currently displaying 1 – 20 of 24

Page 1 Next