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Archiv der Mathematik - A generalized Baumslag–Solitar group is a finitely generated group that acts on a tree with infinite cyclic edge and vertex stabilizers. A group G is residually a... 相似文献
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Let ir(G) and γ(G) be the irredundance number and the domination number of a graph G, respectively. A graph G is called irredundance perfect if ir(H)=γ(H), for every induced subgraph H of G. In this article we present a result which immediately implies three known conjectures on irredundance perfect graphs. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 292–306, 2002 相似文献
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Vadim G. Kessler 《Journal of Sol-Gel Science and Technology》2004,32(1-3):11-17
The article describes the principles of the Single Source Precursor approach to inorganic materials and introduces the Geometrical Molecular Structure Design Concept (MSDC) based on the choice of a proper molecular structure type for the desired precursor and completing it with ligands providing both the necessary number of donor atoms and the sterical protection of the chosen core. Application of MSDC is illustrated with examples taken from development of new approaches in the synthesis of oxide and sulfide catalysts and ferroelectric oxide materials. 相似文献
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Vadim Kaimanovich 《Israel Journal of Mathematics》1995,89(1-3):77-134
Covering Markov operators are a measure theoretical generalization of both random walks on groups and the Brownian motion
on covering manifolds. In this general setup we obtain several results on ergodic properties of their Poisson boundaries,
in particular, that the Poisson boundary is always infinite if the deck group is non-amenable, and that the deck group action
on the Poisson boundary is amenable. For corecurrent operators we show that the Radon-Nikodym cocycles of two quotients of
the Poisson boundary are cohomologous iff these quotients coincide. It implies that the Poisson boundary is either purely
non-atomic or trivial, and that the action of any normal subgroup of the deck group on the Poisson boundary is conservative.
We show that the Poisson boundary is trivial for any corecurrent covering operator with a nilpotent (or, more generally, hypercentral)
deck group. Other applications and examples are discussed.
Supported by a British SERC Advanced Fellowship. A part of this work was done during my stay at MSRI, Berkeley supported by
NSF Grant DMS 8505550. 相似文献
8.
V. A. Varlachev G. N. Dudkin Yu. F. Krechetov V. N. Padalko E. N. Shuvalov 《JETP Letters》2004,80(3):149-151
A nuclear-reactor experiment on the search for the emission of neutral pions from the neutron-induced fission of 235U nuclei has been carried out. To this end, an experimental setup for searching for the emission of π0 mesons with high sensitivity to this process has been designed and produced. This setup consisted of two Cherenkov total-absorption spectrometers for the detection and measurements of the energy of two gamma-ray photons from π 0-meson decay. The spectrometers were placed at the exits of two coaxial horizontal experimental channels. To protect the detectors from low-energy β and γ rays and neutron fluxes, 3.5-m-long water filters were situated in the channels. To reject the cosmic background, large-area scintillation counters operating in the anticoincidence mode were placed over each spectrometer. The energy and time resolution of the spectrometers, as well as the efficiency of detecting charged particles by scintillation counters, were tested on the secondary electron beam of the Tomsk electron synchrotron Sirius. Runs of measurements of the effect on the operating reactor (duration of 805 h) were alternated with runs of measurements of background on the stopped reactor (duration of 403 h). Statistical processing of the experimental results yields an upper limit of ≤5.3×10 ?12 with a 90% confidence level for the probability of the emission of neutral pions from the neutron-induced fission of 235U nuclei. This result and results of other works carried out with sources of spontaneously fissioning 252Cf nuclei show that the probabilities of the emission of π0 mesons from spontaneous fission and fission induced by fission-spectrum neutrons are equal to each other. 相似文献
9.
We consider a class of homogeneous manifolds including all semisimple coadjoint orbits. We describe manifolds of that class
admitting deformation quantizations equivariant under the action ofG and the corresponding quantum group. We also classify Poisson brackets relating to such quantizations.
Presented at the 11th Colloquium “Quantum Groups and Integrable Systems”, Prague, 20–22 June 2002. 相似文献
10.
M. S. Dudkin N. A. Rodionova I. S. Kazanskaya I. V. Gorbacheva E. I. Kozarez N. A. Denisyuk 《Chemistry of Natural Compounds》1981,16(4):338-342
The enzymatic hydrolysis of a 4-0-methylglucuronoxylan of white sweetclover (Melilotus albus) by a highly purified homogeneous endo-1, 4--xylanase fromAspergillus niger 14 has shown that the enzyme hydrolyzes 97% of the polysaccharide in 72 h. Acidic and neutral oligosaccharides were found in the hydrolysate after the action of the enzyme. An investigation of the hexauronic acid isolated has shown that the glucuronic acid is attached to the nonreducing end of the xylooligosaccharide, which demonstrates the specific action of the enzyme on the polysaccharide.M. V. Lomonosov Odessa Technological Institute of the Food Industry. A. N. Bakh Institute of Biochemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 477–483, July–August, 1980. 相似文献