Search results for "F36"
showing 10 items of 38 documents
The proof of Birman’s conjecture on singular braid monoids
2003
Let B_n be the Artin braid group on n strings with standard generators sigma_1, ..., sigma_{n-1}, and let SB_n be the singular braid monoid with generators sigma_1^{+-1}, ..., sigma_{n-1}^{+-1}, tau_1, ..., tau_{n-1}. The desingularization map is the multiplicative homomorphism eta: SB_n --> Z[B_n] defined by eta(sigma_i^{+-1}) =_i^{+-1} and eta(tau_i) = sigma_i - sigma_i^{-1}, for 1 <= i <= n-1. The purpose of the present paper is to prove Birman's conjecture, namely, that the desingularization map eta is injective.
Automorphisms of 2–dimensional right-angled Artin groups
2007
We study the outer automorphism group of a right-angled Artin group AA in the case where the defining graph A is connected and triangle-free. We give an algebraic description of Out.AA/ in terms of maximal join subgraphs in A and prove that the Tits’ alternative holds for Out.AA/. We construct an analogue of outer space for Out.AA/ and prove that it is finite dimensional, contractible, and has a proper action of Out.AA/. We show that Out.AA/ has finite virtual cohomological dimension, give upper and lower bounds on this dimension and construct a spine for outer space realizing the most general upper bound. 20F36; 20F65, 20F28
An intense physical rehabilitation programme determines pain relief and improves the global quality of life in patients with fibromyalgia.
2019
OBJECTIVES:It is accepted that the optimal management of patients with fibromyalgia (FM) requires a combination of non-pharmacological and pharmacological interventions. Our study aimed to analyse the effects of a supplemented physical program on the quality of life of FM patients.METHODS:We enrolled 60 patients, all female (mean age 49±5.7 years), with primary FM (mean years of disease 33±12 months). Patients who agreed to participate in this study met the proposed 1990 American College of Rheumatology classification criteria and the 2010 American College of Rheumatology preliminary diagnostic criteria and were recruited at Policlinico P. Giaccone, University Hospital of Palermo, Italy. Th…
The solution to a conjecture of Tits on the subgroup generated by the squares of the generators of an Artin group
2000
It was conjectured by Tits that the only relations amongst the squares of the standard generators of an Artin group are the obvious ones, namely that a^2 and b^2 commute if ab=ba appears as one of the Artin relations. In this paper we prove Tits' conjecture for all Artin groups. More generally, we show that, given a number m(s)>1 for each Artin generator s, the only relations amongst the powers s^m(s) of the generators are that a^m(a) and b^m(b) commute if ab=ba appears amongst the Artin relations.
Conjugacy problem for braid groups and Garside groups
2003
We present a new algorithm to solve the conjugacy problem in Artin braid groups, which is faster than the one presented by Birman, Ko and Lee. This algorithm can be applied not only to braid groups, but to all Garside groups (which include finite type Artin groups and torus knot groups among others).
On the Toeplitz algebras of right-angled and finite-type Artin groups
1999
The graph product of a family of groups lies somewhere between their direct and free products, with the graph determining which pairs of groups commute and which do not. We show that the graph product of quasi-lattice ordered groups is quasi-lattice ordered, and, when the underlying groups are amenable, that it satisfies Nica's amenability condition for quasi-lattice orders. As a consequence the Toeplitz algebras of these groups are universal for covariant isometric representations on Hilbert space, and their representations are faithful if the isometries satisfy a properness condition given by Laca and Raeburn. An application of this to right-angled Artin groups gives a uniqueness theorem …
Automorphism groups of some affine and finite type Artin groups
2004
We observe that, for fixed n ≥ 3, each of the Artin groups of finite type An, Bn = Cn, and affine type ˜ An−1 and ˜ Cn−1 is a central extension of a finite index subgroup of the mapping class group of the (n + 2)-punctured sphere. (The centre is trivial in the affine case and infinite cyclic in the finite type cases). Using results of Ivanov and Korkmaz on abstract commensurators of surface mapping class groups we are able to determine the automorphism groups of each member of these four infinite families of Artin groups. A rank n Coxeter matrix is a symmetric n × n matrix M with integer entries mij ∈ N ∪ {∞} where mij ≥ 2 for ij, and mii = 1 for all 1 ≤ i ≤ n. Given any rank n Coxeter matr…
Is full banking integration desirable?
2020
The aim of this paper is to analyze the links between banking integration and economic development for a sample of OECD countries. We measure banking integration considering state-of-the-art indicators that measure not only how open a banking system is but also its degree of connectedness with other banking systems. In a second stage, we plug these indicators in a model of economic growth, also controlling for other relevant variables considered by the economic growth literature. In contrast to previous initiatives, this second stage explicitly takes into account the differing levels of economic development of the countries in our sample, since the benefits of enhanced banking inte- gration…
50 years of capital mobility in the eurozone: breaking the Feldstein-Horioka puzzle
2021
AbstractThis paper assesses capital mobility for the Eurozone countries by studying the long-run relationship between domestic investment and savings for the period 1970-2019. Our main goal is to analyze the impact of economic events on capital mobility during this period. We apply the cointegration methodology in a setting that allows us to identify endogenous breaks in the long-run saving-investment relationship. Precisely, the breaks coincide with relevant economic events. We find a downward trend in the saving-investment retention since the 70s for the so-called “core countries”, whereas this trend is not so evident in the peripheral, where the financial and sovereign crises have had a …
FISCALITY – RELEVANT FACTOR INFLUENCING THE BUSINESS ENVIRONMENT
2013
Main tool for macroeconomic management - fiscal policy consists in establishing the levels of taxation and spending in order to influence macroeconomic performance. Fiscal policy, promoted by the government authorities of any contemporary state, is directed usually to achieving microeconomic and macroeconomic goals deriving from the roles the state must fulfill in the economy, respectively the allocative role, distributive, regulatory and the stabilizer role. Governmental authorities, through the production and supply of public goods that are financed at the expense of taxes or duties, or on the public debt, affect both individuals’ utility functions and production functions of economic age…