The selection of task-relevant information from amongst task-irrelevant or distracting information is key to successful performance, and much debate has focused on the processing stage(s) at which this selection takes place. Earlyselection theory claimed that the selection of task-relevant information occurs at an early perceptual level of processing, so that only targets are perceptually encod...

Let G be a finitely generated group and G⊲G1⊲G2⊲. . . be normal subgroups such that ∩k=1Gk = {1}. Let A ∈ Mat d×d(CG) and Ak ∈ Mat d×d(C(G/Gk)) be the images of A under the maps induced by the epimorphisms G → G/Gk. According to the strong form of the Approximation Conjecture of Lück [4] dimG(ker A) = lim k→∞ dimG/Gk(ker Ak) , where dimG denotes the von Neumann dimension. In [2] Dodziuk, Linnel...

Building on recent work of Jaikin-Zapirain, we provide a homological criterion for ring to be pseudo-Sylvester domain, that is, admit division fractions over which all stably full matrices become invertible. We use the study skew Laurent polynomial rings free ideal (firs). As an application our methods, prove crossed products with free-by-{infinite cyclic} and surface groups are domains uncondi...

Let Γ be a finitely generated, amenable group. Using an idea ofÉ. Ghys, we prove that if Γ has a nontrivial, orientation-preserving action on the real line, then Γ has an infinite, cyclic quotient. (The converse is obvious.) This implies that if Γ has a faithful action on the circle, then some finite-index subgroup of Γ has the property that all of its nontrivial, finitely generated subgroups h...

Let X1,…,Xn be operators in a finite von Neumann algebra and consider their division closure the affiliated unbounded operators. We address question when this is skew field (aka ring) it free field. show that first property equivalent to strong Atiyah second can characterized terms of noncommutative distribution X1,…,Xn. More precisely, generate if only there exist no non-zero rank T1,…,Tn such...

F. Cagnacci ([email protected]), M. Neteler, L. Delucchi and F. Ossi, Biodiversity and Molecular Ecology Dept, IASMA Research and Innovation Centre, Fondazione Edmund Mach, Via Mach 1, IT-38010 San Michele all ’ Adige (TN), Italy. FO also at: UMR CNRS 5558 Dept. of Biometry and Evolutionary Biology, Univ. Claude Bernard Lyon1, Bat G. Mendel 43 Bd du 11 Novembre 1918, FR-69622 Villeurb...

Knowledge about the potential spatial dynamics of species is important. Already in 1922, the American ornithologist Joseph Grinnell (Grinnell 1922) noted that in order to understand the population consequences of dispersal, its role in the stochastic nature of rare longdistance movements and the interplay between innate and environmental factors in triggering dispersal, have to be known. Furthe...

Polycyclic groups are one of the best understood class of groups. For example most of the decision problems are decidable in this class, see [7]. It seems surprising therefore that it is still an open problem whether there exists an algorithm which finds d(G) for any polycyclic group G (given by say a set of generators and relations). This is unknown even in the case when G is virtually abelian...

We use elementary methods to compute the L-dimension of the eigenspaces of the Markov operator on the lamplighter group and of generalizations of this operator on other groups. In particular, we give a transparent explanation of the spectral measure of the Markov operator on the lamplighter group found by Grigorchuk-Zuk [4]. The latter result was used by Grigorchuk-Linnell-Schick-Zuk [3] to pro...