In computational anatomy, one needs to perform statistics on shapes and transformations, and to transport these statistics from one geometry (e.g. a given subject) to another (e.g. the template). The geometric structure that appeared to be the best suited so far was the Riemannian setting. The statistical Riemannian framework was indeed pretty well developped for finite-dimensional manifolds an...

Various subsets of the tracial state space of a unital C∗-algebra are studied. The largest of these subsets has a natural interpretation as the space of invariant means. II1-factor representations of a class of C ∗-algebras considered by Sorin Popa are also studied. These algebras are shown to have an unexpected variety of II1-factor representations. This general theory is related to various ot...

The σ -convergence and σ -core of a real bounded sequence were introduced in [R. Raimi, Invariant means and invariant matrix methods of summability, Duke Math. J. 30 (1963) 81–94] and [S.L. Mishra, B. Satapathy, N. Rath, Invariant means and σ -core, J. Indian Math. Soc. 60 (1984) 151–158], respectively. In this work, we extend these ideas to double sequences. c © 2006 Elsevier Ltd. All rights r...

The purpose of this paper is to introduce and study the notion of a vector-valued π-invariant mean associated to a unitary representation π of a locally compact groupG on S, a self-adjoint linear subspace containing I of B(Hπ). We obtain, among other results, an extension theorem for π-invariant completely positive maps and π-invariant means which characterizes amenability of G. We also study v...

In this paper, we define the sequence spaces wσ(u,Δ), [w]σ(u,Δ) and [wσ](u,Δ), where for any sequence x = (xk), the difference sequence Δx is given by Δx = (Δxk)k=1 = (xk − xk−1)k=1. We also study some inclusion relations and properties of the above mentioned spaces. These are generalizations of those defined and studied by Mursaleen, Gaur and Chishti in 1997 and some others. Mathematics Subjec...

First, we recall some notations and definitions which will be used throughout the paper (cf. [12]). A double sequence x = (xjk) of real or complex numbers is said to be bounded if ‖x‖∞ = supj,k |xjk| < ∞. We denote the space of all bounded double sequences by L. A double sequence x = (xjk) is said to converge to the limit L in Pringsheims sense (shortly, p-convergent to L) if for every ε > 0 th...

Face being the most natural method of identification for humans is one of the most significant biometric modalities and various methods to achieve efficient face recognition have been proposed. However the changes in face owing to different expressions, pose, makeup, illumination, age bring about marked variations in the facial image. These changes will inevitably occur and they can be controll...

Different blur invariant descriptors have been proposed so far, which are either in the spatial domain or based on the properties available in the moment domain. In this paper, a frequency framework is proposed to develop blur invariant features that are used to deconvolve a degraded image caused by a Gaussian blur. These descriptors are obtained by establishing an equivalent relationship betwe...

1. Introduction. Invariant means on spaces of functions have been studied by von Neumann [ 7], Banach [ 2], Day [ 4], [5] and others. Day's Amenable semigroups [5] presents a comprehensive summary of the earlier work and many new results. Let 2 be an abstract group or semigroup and ret (2) the Banach space of all bounded real-valued functions on 2 with the supremum norm. A mean on rei(2) is a p...