Search results for "Linear algebra"
showing 10 items of 552 documents
Stability of degenerate parabolic Cauchy problems
2015
We prove that solutions to Cauchy problems related to the $p$-parabolic equations are stable with respect to the nonlinearity exponent $p$. More specifically, solutions with a fixed initial trace converge in an $L^q$-space to a solution of the limit problem as $p>2$ varies.
Goldschmidt Abstracts 2010 – F
2010
We report on two novel procedures for the determination of several trace elements in seawater, including elements characterized by very low abundance (sub-0.1 to 1 ng l-1) in the ocean, such as REEs, Hf, and Th. Our methods are based on the procedure developed recently by Bayon et al. [1], and applied successfully to a wide range of geological samples. It involves addition of a Tm spike and pre-concentration using co-precipitation, prior to analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). The addition of a small amount of Tm to the sample produces a positive Tm anomaly in the resulting REE pattern, which allows calculation of precise trace element concentrat…
Trace and density results on regular trees
2019
We give characterizations for the existence of traces for first order Sobolev spaces defined on regular trees.
An Outline of Morpho-Constructional Analysis
1991
A concept of morpho-constructional analysis is outlined which describes functions of organic features in terms of transformation of energy input into effect output on the strength of physical principles. The dependence of effect outputs on constructional parameters, such as geometrical configurations and material properties, is illustrated in a vector model. It shows that performances of organisms, on principle, can be provided in equivalent manner by different constructional solutions. Options exist in regards to (1) how constructional parameters can be provided by an organism, (2) how particular effects or performances can be produced, and (3) how organizational units can be constrained b…
Bicommutants of reduced unbounded operator algebras
2009
The unbounded bicommutant $(\mathfrak M_{E'})''$ of the {\em reduction} of an O*-algebra $\MM$ via a given projection $E'$ weakly commuting with $\mathfrak M$ is studied, with the aim of finding conditions under which the reduction of a GW*-algebra is a GW*-algebra itself. The obtained results are applied to the problem of the existence of conditional expectations on O*-algebras.
Riesz-like bases in rigged Hilbert spaces
2015
The notions of Bessel sequence, Riesz-Fischer sequence and Riesz basis are generalized to a rigged Hilbert space $\D[t] \subset \H \subset \D^\times[t^\times]$. A Riesz-like basis, in particular, is obtained by considering a sequence $\{\xi_n\}\subset \D$ which is mapped by a one-to-one continuous operator $T:\D[t]\to\H[\|\cdot\|]$ into an orthonormal basis of the central Hilbert space $\H$ of the triplet. The operator $T$ is, in general, an unbounded operator in $\H$. If $T$ has a bounded inverse then the rigged Hilbert space is shown to be equivalent to a triplet of Hilbert spaces.
Polyhedrality and decomposition
2018
Abstract The aim of this note is to present two results that make the task of finding equivalent polyhedral norms on certain Banach spaces, having either a Schauder basis or an uncountable unconditional basis, easier and more transparent. The hypotheses of both results are based on decomposing the unit sphere of a Banach space into countably many pieces, such that each one satisfies certain properties. Some examples of spaces having equivalent polyhedral norms are given.
Simulation investigations of the position of Fatigue Fracture Plane in materials with biaxial loads
1989
In the paper three methods of determination of the expected fatigue fracture plane position under random triaxial stress state have been presented. They are: weight function method, variance method and damage cumulation method. The weight function method for biaxial cyclic loadings has been analysed with digital simulation. The fatigue fracture plane position has been determined with mean values of the direction cosines of principal stress axes. Averaging has been done at angle values with use of weights. Eleven various weights have been presented and their usability has been analysed on the basis of experimental results obtained by Rotvel, and Nishihara-Kawamoto. The weights with good agre…
A coupled cluster study of the 1 1A1g and 1 1B2u states of benzene
1998
A theoretical investigation of the equilibrium structures and harmonic frequencies of the 1 1A1g and 1 1B2u states of benzene is presented. The performance of coupled cluster singles (CCS), the recently proposed CC2 model, and coupled cluster singles and doubles (CCSD) is compared. The CC2 ground and excited states frequencies are a significant improvement of the CCS results and are relatively close to the CCSD results. A comparative analysis of the vibrations in the two electronic states of both C6H6 and C6D6 is presented. The reliability of predicted shifts in harmonic frequencies between the two states and isotopic shifts is estimated on the basis of the convergence in the CCS, CC2, and …
Topological virtual screening: a way to find new anticonvulsant drugs from chemical diversity.
2003
A topological virtual screening (tvs) test is presented, which is capable of identifying new drug leaders with anticonvulsant activity. Molecular structures of both anticonvulsant-active and non active compounds, extracted from the Merck Index database, were represented using topological indexes. By means of the application of a linear discriminant analysis to both sets of structures, a topological anticonvulsant model (tam) was obtained, which defines a connectivity function. On the basis of this model, 41 new structures with anticonvulsant activity have been identified by a topological virtual screening.