Search results for " homogeneous"

showing 10 items of 37 documents

Some algebras of symmetric analytic functions and their spectra

2011

AbstractIn the spectrum of the algebra of symmetric analytic functions of bounded type on ℓp, 1 ≤ p < +∞, and along the same lines as the general non-symmetric case, we define and study a convolution operation and give a formula for the ‘radius’ function. It is also proved that the algebra of analytic functions of bounded type on ℓ1 is isometrically isomorphic to an algebra of symmetric analytic functions on a polydisc of ℓ1. We also consider the existence of algebraic projections between algebras of symmetric polynomials and the corresponding subspace of subsymmetric polynomials.

Pure mathematicsTriple systemGeneral MathematicsFreudenthal magic squareElementary symmetric polynomialStanley symmetric functionComplete homogeneous symmetric polynomialRing of symmetric functionsAlgorithmSymmetric closureMathematicsAnalytic functionProceedings of the Edinburgh Mathematical Society
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A Primer on Carnot Groups: Homogenous Groups, Carnot-Carathéodory Spaces, and Regularity of Their Isometries

2017

AbstractCarnot groups are distinguished spaces that are rich of structure: they are those Lie groups equipped with a path distance that is invariant by left-translations of the group and admit automorphisms that are dilations with respect to the distance. We present the basic theory of Carnot groups together with several remarks.We consider them as special cases of graded groups and as homogeneous metric spaces.We discuss the regularity of isometries in the general case of Carnot-Carathéodory spaces and of nilpotent metric Lie groups.

Pure mathematicsmetric groupssub-finsler geometryengineering.material01 natural sciencesdifferentiaaligeometriasymbols.namesakesub-Finsler geometryMathematics::Metric Geometry0101 mathematics22f3014m17MathematicsPrimer (paint)QA299.6-433homogeneous groupshomogeneous spacesApplied Mathematics010102 general mathematics05 social sciencesryhmäteorianilpotent groupsCarnot groups; homogeneous groups; homogeneous spaces; metric groups; nilpotent groups; sub-Finsler geometry; sub-Riemannian geometry; Analysis; Geometry and Topology; Applied Mathematicssub-riemannian geometrysub-Riemannian geometry43a8053c17Carnot groupscarnot groupsengineeringsymbols22e25Geometry and Topology0509 other social sciences050904 information & library sciencesCarnot cycleAnalysisAnalysis and Geometry in Metric Spaces
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Isometrically Homogeneous and Topologically Homogeneous Continua

2016

Based on the past study of homogeneous continua, this paper concludes that compact connected metric topological groups and isometrically homogeneous continua fall into the following three mutually disjoint classes: (1) indecomposable; (2) aposyndetic and semi-indecomposable; (3) mutually aposyndetic. Among all continua these are special classes with members having extremal properties. Indecomposable isometrically homogeneous continua are characterized as solenoids, and one-dimensional isometrically homogeneous continua are characterized as solenoids or circles. It is shown that path connected isometrically homogeneous continua are locally connected.

Pure mathematicstopological groupsemi-indecomposableGeneral Mathematics010102 general mathematicsisometrically homogeneouscontinuumample01 natural sciences010101 applied mathematicsindecomposablehomogeneousHomogeneousaposyndetic0101 mathematicsMathematicsIndiana University Mathematics Journal
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The use of species in plantations: renaturalisation and reforestation in Sicily

2017

Afforestation and reforestation activities in Sicily have been widespread in the last century, in order to increase the forest cover that was seriously reduced in the former centuries. Notwithstanding this, Sicily is still characterized by only the 12% of the regional surface covered by woods and forest. The reforestation in the last century was carried out using conifers and eucalypts, just in order to ensure a quick protection of slopes and pastureland, coping diffuse erosion events, and those intervention had a remarkable success. Nowadays, the target of enlarging the forest areas in the island is still compulsive, but the use of species, considering the actual knowledge and nature consc…

Settore AGR/05 - Assestamento Forestale E SelvicolturaAfforestation Reforestation GIS Ecologically Homogeneous Areas Woody species
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4D Clifford algebra based on fixed-size representation

2008

Geometric algebra (also known as Clifford algebra) is a powerful mathematical tool that offers a natural and direct way to model geometric objects and their transformations. It is gaining growing attention in different research fields as physics, robotics, CAD/CAM and computer graphics. In particular, 4D geometric algebra implements homogeneous coordinates, which are used to model 3D scenery in most computer graphics applications. The research work on Clifford algebra is actually aimed at finding efficient implementations of the algebra. This paper wants to give a contribution to this research effort by proposing a direct hardware support for geometric algebra operators. The paper introduce…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniClifford algebra Geometric algebra Homogeneous model Fixed-size representation
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Ancora sulle "esplosive palatali" nelle inchieste dell'Atlante Linguistico del Mediterraneo (ALM): i punti albanesi

2021

Tra i «Problemi redazionali» emersi in fase di controllo e organizzazione dei materiali giunti dalla campagna di rilevamenti dell’Atlante Linguistico del Mediterraneo (ALM), Berruto (1971-1973) rileva la proliferazione e l’eterogeneità di alcune scelte grafemiche operate da diversi raccoglitori che, impegnati in una trascrizione più o meno puntuale delle risposte ottenute, avevano interpretato e risolto variamente alcune delle indicazioni previste nel sistema di trascrizione fonetica che accompagnava il Questionario. Particolarmente complesso era emerso il quadro relativo alla trascrizione di alcune consonanti del settore “palatale”, per le quali i grafemi (e i foni a essi corrispondenti) p…

Settore L-FIL-LET/12 - Linguistica ItalianaAmong the «Editorial problems» that emerged during the control and organization of the materials coming from the survey campaign of the Atlante Linguistico del Mediterraneo (ALM) Berruto (1971-1973) notes the proliferation and heterogeneity of some graphemic choices made by different field researchers. As they were engaged in a more or less punctual transcription of the answers obtained they had interpreted and solved differently some of the directions provided in the phonetic transcription system that accompanied the Questionnaire. The picture relating to the transcription of some consonants of the palatal sector had emerged as particularly complex since the graphemes (and the corresponding phones) foreseen in the original system (ALM 1959) were insufficient. Not even the 1971 updates meant to improve the representation of some phonetic features emerged from the investigations in the operations of Response reviewing allowed to obtain a clear homogeneous picture regarding the «plosive palatal» consonants. With regard to the phonetic trait under scrutiny I have already had the opportunity to propose a path aiming to the achievement of possible operational solutions. This has taken place in view of the planned simplification / homologation and transcoding phase from the ALM original system to the IPA one - while proceeding from the examination of the Schedoni’s current state with regard to the surveys referring to central-southern Italy Corsica and Sicily (see Matranga 2019). The scope is now to investigate the same phonetic trait as proven in the materials about the surveys carried out by Lirak Dodbiba in the ALM’s three Albanian points.
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Rappresentazioni e territorio nelle dinamiche del turismo: il caso della Lonely Planet Sicily

2018

L’attuale dibattito sul riordino territoriale del Paese rende nuovamente centrale il concetto di territorio che, da sempre, in una prospettiva geografica pone problemi definitori. Esso può essere, infatti, oggetto di produzioni simboliche e (ri)semantizzazioni in grado di ridefinirlo e di creare specifiche modalità di interazione. A questo proposito, il presente lavoro intende proporre una riflessione su alcune dinamiche di produzione e riproduzione simbolica che interessano il concetto di territorio nel turismo, ambito in cui si può osservare una relazione diretta tra rappresentazione del territorio (intesa anche come narrazione) e possibilità d’azione. In particolare, attraverso il caso s…

Settore M-GGR/02 - Geografia Economico-PoliticaThe current debate about the Italian territorial reorganization makes again fundamental the concept of «territory». This paper aims to reflect on some important dynamics that concern the idea of territory. More in particular I explore in which form it can be (re)semantised through some tourism representations and narrations able to create specific ways of interaction. By taking into account the case study of the Lonely Planet 2017 digital tourist guidebook dedicated to Sicily that splits (and reorganizes) the island in smaller «regions» it is possible to reflect on a complex space dynamic able to redefine the same idea of territory. Indeed the tourist guidebook uses both texts and geographical maps to propose an anthology of homogeneous and coherent destinations to make the Otherness more accessible for the readers. This process demonstrates how symbolic (re)productions of a territory can give rise to specific constructions of places creating different concepts of region and therefore performative spaces and opportunities of «agency». In other terms the (re)definition of the Sicilian territory proposed by the guide invites tourists to consider a new (narrated) geography invites and invites to interact with it thinking as visitors. From a geographical and cultural point of view reflection on these dynamics allows us to consider some (re)definitions of space in relation to forms of textualization (even on the maps). An imaginary but performative geography that attributes to the concept of territory epistemological and gnoseological possibilities.Settore M-GGR/01 - Geografia
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A non-homogeneous Poisson based model for daily rainfall data

2007

In this paper we report some results of the application of a new stochastic model applied to rainfall daily data. The Poisson models, characterized only by the expected rate of events (impulse occurrences, that is the mean number of impulses per unit time) and the assigned probability distribution of the phenomenon magnitude, do not take into consideration the datum regarding the duration of the occurrences, that is fundamental from a hydrological point of view. In order to describe the phenomenon in a way more adherent to its physical nature, we propose a new model simple and manageable. This model takes into account another random variable, representing the duration of the rainfall due to…

Stochastic modellingSettore SECS-S/02 - Statistica Per La Ricerca Sperimentale E TecnologicaGeodetic datumConfidence Region Daily Rainfall Data Linear Stochastic Differential Equation Poisson White Noise Probabilistic Engineer MechanicsImpulse (physics)Poisson distributionsymbols.namesakeNon homogeneousStatisticssymbolsProbability distributionSettore ICAR/08 - Scienza Delle CostruzioniRandom variableConfidence regionMathematics
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A simplified analysis for the evaluation of stochastic response of elasto-plastic oscillators

1999

Abstract The paper deals with dynamic hysteretic oscillators without post-yielding hardening, called ideal elasto-plastic oscillators, subjected to white noise. They are characterized by the fact that they do not reach stationarity even though excited by stationary stochastic processes. A simplified solution procedure to capture this behaviour is presented in this paper. It is based on modelling the accumulated plastic deformations as a homogeneous compound Poisson process. In particular, two aspects are addressed in the paper: (1) evaluation of the probabilistic parameters of the accumulated plastic deformation process; and (2) evaluation of the second-order cumulants of the response by me…

Stochastic processMechanical EngineeringMonte Carlo methodProbabilistic logicAerospace EngineeringHomogeneous compound Poisson process modelOcean EngineeringStatistical and Nonlinear PhysicsWhite noiseCondensed Matter PhysicsElastoplastic oscillatorsNuclear Energy and EngineeringCompound Poisson processCalculusHardening (metallurgy)Applied mathematicsRandom vibrationElastoplastic oscillators; Homogeneous compound Poisson process modelCivil and Structural EngineeringMathematicsParametric statisticsProbabilistic Engineering Mechanics
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A new efficient, highly dispersed, Pd nanoparticulate silica supported catalyst synthesized from an organometallic precursor. Study of the homogeneou…

2018

[EN] A new Pd(0) catalyst supported on silica UVM-7 has been synthesized from the organometallic [Pd-2(mu-(C6H4) Pp(2))(2)(CH3CN)(4)](BF4)(2) precursor, characterized by the high dispersion, activity, and small size of the palladium nanoclusters fixed on the silica surface. The catalyst was tested for the Suzuki-Miyaura (SM) reaction of different 4-substitutedphenyl halides with phenylboronic acid. The kinetic study concurs with most of the catalytic action was carried out by Pd species originated by the partial solubilization of Pd immobilized on mesoporous silica. The Schmidt's analysis of differential selectivity (SADS) in several competitive SM reactions, together the STEM-HAADF and HRT…

UVM-7 silicaHeterogeneous homogeneous catalysischemistry.chemical_element010402 general chemistryHeterogeneous catalysisHRTEM XRD01 natural sciencesCatalysisNanoclustersCatalysisSuzuki-Miyaurachemistry.chemical_compoundPhysical and Theoretical ChemistryPhenylboronic acidHigh-resolution transmission electron microscopySTEM-HAADF010405 organic chemistryQUIMICA INORGANICAMesoporous silicaPalladium nanoparticles0104 chemical sciencesKinetic studychemistryChemical engineeringSelectivityPalladiumJournal of Catalysis
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