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1.
Peter Brinkmann 《Geometriae Dedicata》2002,93(1):191-203
We present necessary and sufficient conditions for the existence of a splitting over nn3778v626/xxlarge8484.gif" alt="Zopf" align="BASELINE" BORDER="0"> of the mapping torus
nn3778v626/10711_2004_Article_403441_TeX2GIFIE1.gif" alt="
$$M_\Phi = F \times _\Phi {\mathbb{Z}}$$
" align="middle" border="0">
of a free group automorphism nn3778v626/xxlarge934.gif" alt="PHgr" align="BASELINE" BORDER="0">. 相似文献
2.
Let X and Y be metrizable spaces. We show that, for a mapping f : X nn8717/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> Y, there exists a quasi-metric nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0"> X inducing the topology of X such that f regarded as a mapping from (X, max{nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0">, nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0">–1}) to Y is continuous if and only if f in the original topology of X is a nn8717/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">-discrete map of Borel class 1. Further, we prove that, for every nn8717/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">-discrete mapping f: X nn8717/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> Y of Borel class nn8717/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> + 1, there exists a compatible quasi-metric nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0"> on X such that f : (X, max{nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0">, nn8717/xxlarge1009.gif" alt="rhov" align="MIDDLE" BORDER="0">–1}) nn8717/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> Y is of Borel class nn8717/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">. We also investigate a more general situation when the range of the mapping under consideration is not necessarily metrizable. In passing, we obtain some results related to the behaviour of absolutely Borel sets and absolutely analytic spaces with respect to compatible quasi-metrics. 相似文献
3.
4.
Elisabeth Silbernagel Helmut Spreitzer Gerhard Buchbauer 《Monatshefte für Chemie / Chemical Monthly》1990,121(5):433-436
Summary From the pentane extract of the dried leaves ofArtemisia afra JACQ, an Asteraceae native in Southern Africa, the following non volatile constituents have been isolated: Cerylcerotinate, a wax ester, the hydrocarbon nonacosane and the triterpenes friedelin, nn68r313nq5778j7/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">- and nn68r313nq5778j7/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-amyrin. The relative high content of cerylcerotinate in this plant (0.25%) is noteworthy. 相似文献
5.
FE Menéndez Aránzazu Espina Camino Trobajo José R. García Julio Rodríguez 《Journal of inclusion phenomena and macrocyclic chemistry》1994,15(3):215-230
The intercalation reactions betweenn-alkylamines and nn5472034903p252/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-titanium phosphate in aqueous media have been investigated. The compounds with the maximum intercalation have the formula nn5472034903p252/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Ti(HOPO3)2 · 2 C
n
H
2n+1
NH2 · H2O (n=1–10). Defined crystalline phases with lower amine content are described, the general formula being nn5472034903p252/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Ti(HOPO3)2 ·
m
C
n
H
2n+1
NH2 ·pH2O (m=1.0 1.3, 1.5, 1.7). Whenm=1.0 then-alkylamines form a monomolecular layer. Whenm>1.0 the layer is bimolecular. The inclination angle and the packing density of then-alkylamines in the interlayer space is determined. 相似文献
6.
The series of nn11707672502m/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">,nn11707672502m/xxlarge969.gif" alt="ohgr" align="BASELINE" BORDER="0">-diiodopermethylpolysilanes, I(SiMe
2)
n
I, (n=4–6) andX(SiMe
2)4
X, (X=Cl, Br) has been prepared by the action of halogen on the corresponding cyclic compounds (SiMe
2)
n
. The mass spectra, NMR-, IR- andRaman-spectra of these compounds have been recorded.
Herrn Prof. Dr.Josef Schurz zum 60. Geburtstag gewidmet. 相似文献
7.
Reinhard Siegmund-Schultze 《Physics in Perspective (PIP)》2007,9(1):26-57
The theoretical physicist Philipp Frank (1884–1966) and the applied mathematician Richard von Mises (1883–1953) both received
their university education in Vienna shortly after 1900 and became friends at the latest during the Great War.They were attached
to the Vienna Circle of Logical Positivists and wrote an influential two-part work on the differential and integral equations
of mechanics and physics, the Frank-Mises, of 1925 and 1927, with its second edition following in 1930 and 1935.This work
originated in the lectures that the mathematician Bernhard Riemann (1826–1866) delivered on partial differential equations
and their applications to physical questions at the University of G?ttingen between 1854 and 1862, which were edited and published
posthumously in1869 by the physicist Karl Hattendorff (1834–1882).The immediate precursor of the Frank-Mises, however, was
the extensive revision of Hattendorff’s edition of Riemann’s lectures that the mathematician Heinrich Weber (1842–1913) published
in two volumes, the Riemann-Weber, of 1900 and 1901, with its second edition following in 1910 and 1912. I trace this historical
lineage, explore the nature and contents of the Frank-Mises, and discuss its complementary relationship to the first volume
of the text that the mathematicians Richard Courant (1888–1972) and David Hilbert (1862–1943) published on the methods of
mathematical physics in 1924, the Courant-Hilbert,which, when it and its second volume of 1937 were translated into English
and extensively revised in 1953 and 1961, eclipsed the classic Frank-Mises. 相似文献
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