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31.
It is shown that the punctual quotient schemeQ
l
r
parametrizing all zero-dimensional quotients
of lengthl and supported at some fixed point O∈A
2 in the plane is irreducible. 相似文献
32.
Geir Kildahl-Andersen 《Tetrahedron letters》2006,47(27):4693-4696
Isoprenoid acyclic polyene carbodications with 6, 14 and 18 π electrons have been synthesized and characterized in comparison with previously prepared dicyclic C40-carotenoid dications. An equation correlating λmax (400-1100 nm region) and the number of sp2 hybridized carbon atoms in the dication is presented. 相似文献
33.
Geir Pedersen 《国际流体数值方法杂志》1986,6(8):497-505
Propagation of periodic waves in the vicinity of irregular saw-tooth shaped boundary in finite difference models is investigated. The reflection of an incoming wave from a single saw-tooth boundary is found to be accompanied by a phase shift. It is shown that any wave mode propagating along such a boundary is trapped and decays in the direction normal to the boundary. A wave propagating along a channel with saw-tooth shaped lateral boundaries is influenced by the trapped waves, which leads to a reduction of the phase velocity. Phase velocities obtained from the present normal mode analysis are compared to velocities in numerical experiments. The agreement is excellent. 相似文献
34.
Depth‐averaged non‐hydrostatic extension for shallow water equations with quadratic vertical pressure profile: equivalence to Boussinesq‐type equations 下载免费PDF全文
We reformulate the depth‐averaged non‐hydrostatic extension for shallow water equations to show equivalence with well‐known Boussinesq‐type equations. For this purpose, we introduce two scalars representing the vertical profile of the non‐hydrostatic pressure. A specific quadratic vertical profile yields equivalence to the Serre equations, for which only one scalar in the traditional equation system needs to be modified. Equivalence can also be demonstrated with other Boussinesq‐type equations from the literature when considering variable depth, but then the non‐hydrostatic extension involves mixed space–time derivatives. In case of constant bathymetries, the non‐hydrostatic extension is another way to circumvent mixed space–time derivatives arising in Boussinesq‐type equations. On the other hand, we show that there is no equivalence when using the traditionally assumed linear vertical pressure profile. Linear dispersion and asymptotic analysis as well as numerical test cases show the advantages of the quadratic compared with the linear vertical non‐hydrostatic pressure profile in the depth‐averaged non‐hydrostatic extension for shallow water equations. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
35.
Geir Langli 《合成通讯》2013,43(2):309-315
The preparation of an annulated verbenyl indene is described. Reduction of the verbenone oxo group and water elimination provided a verbenylindene with an embedded fulvene unit, which was reduced to an annulated verbenylindene, a fluorene derivative. The ansa‐bridge was constructed between the fluorene 9‐position and 6,6‐dimethylfulvene by way of the lithiated indene. Dilithiation of the ligand and treatment with ZrCl4 yielded the corresponding zirconocene. 相似文献
36.
The paper presents a semantics for quantified modal logic which has a weaker axiomatization than the usual Kripke semantics. In particular, the Barcan Formula (BF) and its converse are not valid with the proposed semantics. Subclasses of models which validate BF and other interesting formulas are presented. A completeness theorem is proved, and the relation between this result and completeness with respect to Kripke models is investigated. 相似文献
37.
The solubility of aluminium orthophosphate in cryolite melts was determined. Part of the binary phase diagram of the system Na3AlF6-AlPO4 was investigated. The eutectic point was determined to be at 43.7 mass% (or 57.2 mol%) AlPO4 and (696 ± 1) °C. It is suggested that in pure molten cryolite melts the orthophosphate ion dissociates partly into a metaphosphate ion and an oxide ion. 相似文献
38.
Geir Ellingsrud Stein Arild Strø mme 《Journal of the American Mathematical Society》1996,9(1):175-193
We outline a strategy for computing intersection numbers on
smooth varieties with torus actions using a residue formula of Bott. As an example, Gromov-Witten numbers of twisted cubic and elliptic quartic curves on some general complete intersection in projective space are computed. The results are consistent with predictions made from mirror symmetry computations. We also compute degrees of some loci in the linear system of plane curves of degrees less than 10, like those corresponding to sums of powers of linear forms, and curves carrying inscribed polygons.
smooth varieties with torus actions using a residue formula of Bott. As an example, Gromov-Witten numbers of twisted cubic and elliptic quartic curves on some general complete intersection in projective space are computed. The results are consistent with predictions made from mirror symmetry computations. We also compute degrees of some loci in the linear system of plane curves of degrees less than 10, like those corresponding to sums of powers of linear forms, and curves carrying inscribed polygons.
39.
Geir B. Asheim 《International Journal of Game Theory》2002,30(4):453-478
Proper consistency is defined by the property that each player takes all opponent strategies into account (is cautious) and deems one opponent strategy to be infinitely more likely than another if the opponent prefers the one to the other (respects preferences). When there is common certain belief of proper consistency, a most preferred strategy is properly rationalizable. Any strategy used with positive probability in a proper equilibrium is properly rationalizable. Only strategies that lead
to the backward induction outcome are properly rationalizable in the strategic form of a generic perfect information game.
Proper rationalizability can test the robustness of inductive procedures.
Final version: December 2001 相似文献
40.
In this article, a unified approach to obtain symplectic integrators on \(T^{*}G\) from Lie group integrators on a Lie group \(G\) is presented. The approach is worked out in detail for symplectic integrators based on Runge–Kutta–Munthe-Kaas methods and Crouch–Grossman methods. These methods can be interpreted as symplectic partitioned Runge–Kutta methods extended to the Lie group setting in two different ways. In both cases, we show that it is possible to obtain symplectic integrators of arbitrarily high order by this approach. 相似文献