Search results for "PPI"

showing 10 items of 7396 documents

On the structure of the set of equivalent norms on ℓ1 with the fixed point property

2012

Abstract Let A be the set of all equivalent norms on l 1 which satisfy the FPP. We prove that A contains rays. In fact, every renorming in l 1 which verifies condition (⁎) in Theorem 2.1 is the starting point of a (closed or open) ray composed by equivalent norms on l 1 with the FPP. The standard norm ‖ ⋅ ‖ 1 or P.K. Linʼs norm defined in Lin (2008) [12] are examples of such norms. Moreover, we study some topological properties of the set A with respect to some equivalent metrics defined on the set of all norms on l 1 equivalent to ‖ ⋅ ‖ 1 .

CombinatoricsDiscrete mathematicsRenorming theoryApplied MathematicsNorm (mathematics)Fixed-point theoremNonexpansive mappingsFixed point theoryEquivalence of metricsFixed-point propertyStabilityAnalysisMathematicsJournal of Mathematical Analysis and Applications
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Mappings of finite distortion: discreteness and openness for quasi-light mappings

2005

Abstract Let f ∈ W 1 , n ( Ω , R n ) be a continuous mapping so that the components of the preimage of each y ∈ R n are compact. We show that f is open and discrete if | D f ( x ) | n ⩽ K ( x ) J f ( x ) a.e. where K ( x ) ⩾ 1 and K n − 1 / Φ ( log ( e + K ) ) ∈ L 1 ( Ω ) for a function Φ that satisfies ∫ 1 ∞ 1 / Φ ( t ) d t = ∞ and some technical conditions. This divergence condition on Φ is shown to be sharp.

CombinatoricsDistortion (mathematics)Open mappingApplied MathematicsHausdorff dimensionMathematical analysisFunction (mathematics)Mathematical PhysicsAnalysisMathematicsAnnales de l'Institut Henri Poincaré C, Analyse non linéaire
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Old and New on the Quasihyperbolic Metric

1998

Let D be a proper subdomain of \( {\mathbb{R}^d}\). Following Gehring and Palka [GP] we define the quasihyperbolic distance between a pair x 1, x 2 of points in D as the infimum of \( {\smallint _\gamma }\frac{{ds}}{{D\left( {x,\partial D} \right)}}\) over all rectifiable curves γ joining x 1, x 2 in D. We denote the quasihyperbolic distance between x 1, x 2 by k D (x 1, x 2). As pointed out by Gehring and Osgood [GO], x 1 and x 2 can be joined by a quasihyperbolic geodesic; also see [Mr]. The quasihyperbolic metric is comparable to the usual hyperbolic metric in a simply connected plane domain by the Koebe distortion theorem. For a multiply connected plane domain D these two metrics are co…

CombinatoricsDistortion (mathematics)Quasiconformal mappingGeodesicHausdorff dimensionMetric (mathematics)Simply connected spaceBoundary (topology)Domain (mathematical analysis)Mathematics
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Residual 𝑝 properties of mapping class groups and surface groups

2008

Let M ( Σ , P ) \mathcal {M}(\Sigma , \mathcal {P}) be the mapping class group of a punctured oriented surface ( Σ , P ) (\Sigma ,\mathcal {P}) (where P \mathcal {P} may be empty), and let T p ( Σ , P ) \mathcal {T}_p(\Sigma ,\mathcal {P}) be the kernel of the action of M ( Σ , P ) \mathcal {M} (\Sigma , \mathcal {P}) on H 1 ( Σ ∖ P , F p ) H_1(\Sigma \setminus \mathcal {P}, \mathbb {F}_p) . We prove that T p ( Σ , P ) \mathcal {T}_p( \Sigma ,\mathcal {P}) is residually p p . In particular, this shows that M ( Σ , P ) \mathcal {M} (\Sigma ,\mathcal {P}) is virtually residually p p . For a group G G we denote by I p ( G ) \mathcal {I}_p(G) the kernel of the natural action of Out ⁡ ( G ) \ope…

CombinatoricsKernel (algebra)Class (set theory)Conjugacy classGroup (mathematics)Applied MathematicsGeneral MathematicsOrder (group theory)Property aGeometrySurface (topology)Mapping class groupMathematicsTransactions of the American Mathematical Society
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The best choice problem with an unknown number of objects

1993

The secretary problem with a known prior distribution of the number of candidates is considered. Ifp(i)=p(N=i),i ∈ [α, β] ∩ ℕ, whereα=inf{i ∈ℕ:p(i) > 0} andβ=sup{i ∈ℕ:p(i)≳0}, is the prior distribution of the numberN of candidates it will be shown that, if the optimal stopping rule is of the simple form, then the optimal stopping indexj=minΓ satisfies asymptotically (asβ → ∞) the equationj=exp $${{\left[ {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i) \log (i)/i} } \right)} \right]} \mathord{\left/ {\vphantom {{\left[ {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i) \log (i)/i} } \right)} \right]} {\left. {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i)/i} } \right) - 1} \ri…

CombinatoricsStopping setGeneral MathematicsStopping ruleCalculusOptimal stopping ruleManagement Science and Operations ResearchChoice problemSoftwareMathematicsZOR Zeitschrift f�r Operations Research Methods and Models of Operations Research
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Absolute continuity of mappings with finite geometric distortion

2015

Suppose that ⊂ R n is a domain with n ≥ 2. We show that a continuous, sense-preserving, open and discrete mapping of finite geometric outer distortion with KO(·,f) ∈ L 1/(n 1) loc () is absolutely continuous on almost every line parallel to the coordinate axes. Moreover, if U ⊂ is an open set with N(f,U) 0 depends only on n and on the maximum multiplicity N(f,U).

Combinatoricsmappings of finite distortionGeneral Mathematicsta111Mathematical analysisOpen setA domainMultiplicity (mathematics)Absolute continuitymoduli inequalitiesGeometric distortionq-mappingsMathematicsAnnales Academiae Scientiarum Fennicae Mathematica
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IMPLICACIONES DEL USO DE BUSCADORES EN EL COMPORTAMIENTO DE COMPRA ONLINE / IMPLICATIONS OF THE SEARCH ENGINES USE IN THE ONLINE SHOPPING BEHAVIOUR

2009

El objetivo del presente trabajo es analizar los factores que influyen en el uso de buscadores y su incidencia en el comportamiento de compra en Internet. El análisis de resultados obtenidos a partir de una muestra representativa de 485 compradores por Internet españoles, pone de manifiesto que los consumidores que consideran la comodidad, reducciones de precio y amplitud de surtido como motivaciones relevantes para realizar compras online presentan una mayor predisposición al uso de buscadores en la realización de sus compras virtuales. La experiencia como internauta y como comprador en Internet son factores que influyen negativamente en el uso de buscadores para la realización de compras …

Comercio Electrónico Motivaciones de compra Buscadores Comportamiento del Consumidor E-commerce Shopping Orientations Search Engines Consumer BehaviourInvestigaciones Europeas de Dirección y Economía de la Empresa
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Internacionalización de empresas a través de clústeres: análisis bibliométrico de palabras clave de 152 publicaciones destacadas en el período 2009-2…

2022

[EN] While countless studies on the role of clusters in regional economic developments and business performance have been done, some disadvantages and limitations also have been identified. Limitations such as small local markets, limited resources, isolation, and over-independence which lead companies to a lock-in state regarding knowledge and innovation can be solved by means of internationalization or foreign market expansion. Therefore, the internationalization of clusters still needs more attention. Furthermore, by conducting a bibliometric study based on the keywords from previous research, this investigation intends to identify the principal and most influential items, their relation…

Commercemapeo bibliométricoF06UNESCO::CIENCIAS ECONÓMICASSciMATR01HF1-6182internacionalizaciónanálisis de palabras clavebibliometric mappingSJRkeyword analysisinternationalizationclustering
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Fixed points in weak non-Archimedean fuzzy metric spaces

2011

Mihet [Fuzzy $\psi$-contractive mappings in non-Archimedean fuzzy metric spaces, Fuzzy Sets and Systems, 159 (2008) 739-744] proved a theorem which assures the existence of a fixed point for fuzzy $\psi$-contractive mappings in the framework of complete non-Archimedean fuzzy metric spaces. Motivated by this, we introduce a notion of weak non-Archimedean fuzzy metric space and prove that the weak non-Archimedean fuzzy metric induces a Hausdorff topology. We utilize this new notion to obtain some common fixed point results for a pair of generalized contractive type mappings.

Common fixed points Weak non-Archimedean fuzzy metric spaces Fuzzy contractive mappingsDiscrete mathematicsFuzzy classificationMathematics::General MathematicsLogicInjective metric spaceT-normFuzzy subalgebraIntrinsic metricConvex metric spaceComputingMethodologies_PATTERNRECOGNITIONSettore MAT/05 - Analisi MatematicaArtificial IntelligenceFuzzy set operationsFuzzy numberComputingMethodologies_GENERALMathematicsFuzzy Sets and Systems
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Common fixed point theorems of integral type for OWC mappings under relaxed condition

2017

In this paper, we prove a common fixed point theorem for a pair of occasionally weakly compatible (owc) self mappings satisfying a mixed contractive condition of integral type without using the triangle inequality. We prove also analogous results for two pairs of owc self mappings by assuming symmetry only on the set of points of coincidence. These results unify, extend and complement many results existing in the recent literature. Finally, we give an application of our results in dynamic programming.

Common fixed points Weakly compatible mappings Occasionally weakly compatible mappings Contractive condition of integral type Symmetric spacesSettore MAT/05 - Analisi Matematica
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