Search results for "COMPOSITION"

showing 10 items of 2675 documents

Degassing regime of Hekla volcano 2012-2013

2015

Hekla is a frequently active volcano with an infamously short pre-eruptive warning period. Our project contributes to the ongoing work on improving Hekla's monitoring and early warning systems. In 2012 we began monitoring gas release at Hekla. The dataset comprises semi-permanent near-real time measurements with a MultiGAS system, quantification of diffuse gas flux, and direct samples analysed for composition and isotopes (δ13C, δD and δ18O). In addition, we used reaction path modelling to derive information on the origin and reaction pathways of the gas emissions.Hekla's quiescent gas composition was CO2-dominated (0.8mol fraction) and the δ13C signature was consistent with published value…

Dikegeographygeography.geographical_feature_categoryδ18OEarth scienceHydrothermal circulationSettore GEO/08 - Geochimica E VulcanologiaImpact craterVolcanoGeochemistry and PetrologyMagmaGas compositionPetrologyGeologyGroundwater
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Die darstellung von [(CH3)3PRu(CO)2Cl2]2 und [(Ch3)3P]2Ru(CO)2Cl2; Eine berichtigung zu: Die alkoholyse des triethylsilans katalysiert von [(Ch3)3P]2…

1984

Abstract The ruthenium(II) complex used as a catalyst in reactions of alcohols and Et 3 SiH proved to be the dimer [(CH 3 ) 3 PRu(CO) 2 Cl 2 ] 2 and not the complex [(CH 3 ) 3 P] 2 Ru(CO) 2 Cl 2 . Both complexes were prepared, characterized and their catalytic properties were compared.

DimerOrganic ChemistryTrimethylphosphinechemistry.chemical_elementAlcoholBiochemistryMedicinal chemistryCatalysisRutheniumInorganic Chemistrychemistry.chemical_compoundchemistryMaterials ChemistryOrganic chemistryPhysical and Theoretical ChemistryChemical compositionJournal of Organometallic Chemistry
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Co-occurrence of discourse markers in English : from juxtaposition to composition

2019

Abstract In this paper, we report on a qualitative analysis of co-occurring discourse markers, that is, sequences of adjacent discourse markers that belong to the same unit but may express different functions. We examine several formal and functional features of these co-occurring strings on the basis of corpus examples extracted from conversational data in English. In particular, we focus on scope, meaning-in-context (or functions), syntactic category and position. Our analysis reveals several degrees of integration: differences in scope allow us to differentiate juxtaposition and combination of markers. In the case of combination, difference in meaning integration allows us to distinguish…

Discourse markers050101 languages & linguisticsLinguistics and LanguageComputer scienceScope05 social sciencesCo-occurrenceDM co-occurrenceCorpus050105 experimental psychologyLanguage and LinguisticsLinguisticsLanguages and LiteraturesFocus (linguistics)AnnotationSyntactic categoryArtificial IntelligenceEnglishPragmatic functions0501 psychology and cognitive sciencesComposition (language)Scope (computer science)Discourse markerMeaning (linguistics)
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$(BV,L^p)$-decomposition, $p=1,2$, of Functions in Metric Random Walk Spaces

2019

In this paper we study the $(BV,L^p)$-decomposition, $p=1,2$, of functions in metric random walk spaces, a general workspace that includes weighted graphs and nonlocal models used in image processing. We obtain the Euler-Lagrange equations of the corresponding variational problems and their gradient flows. In the case $p=1$ we also study the associated geometric problem and the thresholding parameters.

Discrete mathematicsApplied MathematicsImage processingWorkspaceRandom walkThresholding05C80 35R02 05C21 45C99 26A45Mathematics - Analysis of PDEsMetric (mathematics)Decomposition (computer science)FOS: MathematicsAnalysisMathematicsAnalysis of PDEs (math.AP)
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A matrix of combinatorial numbers related to the symmetric groups

1979

For permutation groups G of finite degree we define numbers t"B(G)=|G|^-^[email protected]?"R"@?"[email protected]?"1(1a"1(g))^b^"^i, where B=(b"1,...,b"1) is a tuple of non-negative integers and a"1(g) denotes the number of i cycles in the element g. We show that t"B(G) is the number of orbits of G, acting on a set @D"B(G) of tuples of matrices. In the case G=S"n we get a natural interpretation for combinatorial numbers connected with the Stiring numbers of the second kind.

Discrete mathematicsCombinatoricsMatrix (mathematics)Degree (graph theory)Symmetric groupDiscrete Mathematics and CombinatoricsFunction compositionPermutation groupTupleElement (category theory)Theoretical Computer ScienceInterpretation (model theory)MathematicsDiscrete Mathematics
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Factorization of homomorphisms through H∞(D)

2003

AbstractWeakly compact homomorphisms between (URM) algebras with connected maximal ideal space are shown to factor through H∞(D) by means of composition operators and to be strongly nuclear. The spectrum of such homomorphisms is also described. Strongly nuclear composition operators between algebras of bounded analytic functions are characterized. The path connected components of the space of endomorphisms on H∞(D) in the uniform operator topology are determined.

Discrete mathematicsConnected spacePure mathematicsEndomorphismCompact spaceComposition operatorBounded functionApplied MathematicsSpectrum (functional analysis)Maximal idealOperator theoryAnalysisMathematicsJournal of Mathematical Analysis and Applications
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The terminal hyperspace of homogeneous continua

2010

Abstract We investigate the structure of the collection of terminal subcontinua in homogeneous continua. The main result is a reduction of this structure to six specific types. Three of these types are of one-dimensional spaces, and examples representing these types are known. It is not known whether higher dimensional examples having non-trivial terminal subcontinua and representing the three remaining types exist.

Discrete mathematicsDecompositionPure mathematicsReduction (recursion theory)Continuum (topology)TerminalStructure (category theory)IndecomposableHyperspaceIntrinsicTerminal (electronics)Tree-likeHomogeneousContinuumHomogeneousGeometry and TopologyIndecomposable moduleMathematicsTopology and its Applications
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A decomposition theorem for compact-valued Henstock integral

2006

We prove that if X is a separable Banach space, then a measurable multifunction Γ : [0, 1] → ck(X) is Henstock integrable if and only if Γ can be represented as Γ = G + f, where G : [0, 1] → ck(X) is McShane integrable and f is a Henstock integrable selection of Γ.

Discrete mathematicsIntegrable systemSelection (relational algebra)MultifunctionHenstock integralIf and only ifGeneral MathematicsBanach spacePettis integralKurzweil–Henstock–Pettis integral selectionSeparable spaceMathematicsDecomposition theorem
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On the optimal approximation rate of certain stochastic integrals

2010

AbstractGiven an increasing function H:[0,1)→[0,∞) and An(H)≔infτ∈Tn(∑i=1n∫ti−1ti(ti−t)H(t)2dt)12, where Tn≔{τ=(ti)i=0n:0=t0<t1<⋯<tn=1}, we characterize the property An(H)≤cn, and give conditions for An(H)≤cnβ and An(H)≥1cnβ for β∈(0,1), both in terms of integrability properties of H. These results are applied to the approximation of stochastic integrals.

Discrete mathematicsMathematics(all)Numerical AnalysisRegular sequencesGeneral MathematicsApplied MathematicsStochastic integralsNon linear approximationFunction (mathematics)CombinatoricsNon-linear approximationFunction compositionAnalysisMathematicsJournal of Approximation Theory
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Dyck paths with a first return decomposition constrained by height

2018

International audience; We study the enumeration of Dyck paths having a first return decomposition with special properties based on a height constraint. We exhibit new restricted sets of Dyck paths counted by the Motzkin numbers, and we give a constructive bijection between these objects and Motzkin paths. As a byproduct, we provide a generating function for the number of Motzkin paths of height k with a flat (resp. with no flats) at the maximal height. (C) 2018 Elsevier B.V. All rights reserved.KeywordsKeyWords Plus:STATISTICS; STRINGS

Discrete mathematicsMathematics::CombinatoricsFirst return decompositionDyck and Motzkin pathsEnumerationHeightStatisticsGenerating function0102 computer and information sciences01 natural sciencesConstructiveTheoretical Computer ScienceConstraint (information theory)Combinatorics010104 statistics & probability010201 computation theory & mathematicsEnumerationBijectionDecomposition (computer science)Discrete Mathematics and CombinatoricsStrings0101 mathematics[MATH]Mathematics [math]MathematicsPeak
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