The main result of the paper is a theorem, using which a new proof of Roth’s theorem is obtained, a new solvability criterion
for the matrix equation AX-YB = C is proved, a formula for a particular solution of the latter is derived, and the least of
the orders of square nonsingular matrices containing a given rectangular matrix as a submatrix is determined. Bibliography:
5 titles.
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 323, 2005, pp. 15–23. 相似文献
An expression for the ratio of the glass transition temperature to the melting temperature, Tg/Tm, was derived with allowance for fluctuations of the packing factor in the amorphous state. This relationship made it possible to describe the actual range of variation in Tg/Tm depending on a change in the packing factor in the crystalline state ko, cr. The proposed approach forms the basis for the method of determination of increments in the packing ratio ko, cr and formulation of the principles of selection of experimental data for calculations. The glass transition temperatures in polyethylene depending on the type of unit cell were calculated. 相似文献
In this paper, a two-dimensional finite volume unstructured mesh method (FVUM) based on a triangular background interpolation mesh is developed for analysing the evolution of the saltwater intrusion into single and multiple coastal aquifer systems. The model formulation consists of a ground-water flow equation and a salt transport equation. These coupled and non-linear partial differential equations are transformed by FVUM into a system of differential/algebraic equations, which is solved using backward differentiation formulas of order one through five. Simulation results are compared with previously published solutions where good agreement is observed. 相似文献
The solar wind almost disappeared on May 11, 1999: the solar wind plasma density and dynamic pressure were less than 1cm−3 and 0.1 nPa respectively, while the interplanetary magnetic field was northward. The polar ionospheric data observed by the multi-instruments at Zhongshan Station in Antarctica on such special event day was compared with those of the control day (May 14). It was shown that geomagnetic activity was very quiet on May 11 at Zhongshan. The magnetic pulsation, which usually occurred at about magnetic noon, did not appear. The ionosphere was steady and stratified, and the F2 layer spread very little. The critical frequency of day-side F2 layer, f0F2, was larger than that of control day, and the peak of f0F2 appeared 2 hours earlier. The ionospheric drift velocity was less than usual. There were intensive auroral Es appearing at magnetic noon. All this indicates that the polar ionosphere was extremely quiet and geomagnetic field was much more dipolar on May 11. There were some signatures of auroral substorm before midnight, such as the negative deviation of the geomagnetic H component, accompanied with auroral Es and weak Pc3 pulsation.
Optics and Spectroscopy - The relationship between the parameters of quadripoles (mirrors, for example) ensuring the fulfillment of the energy conservation law are considered. Apart from the... 相似文献
H. Crapo raised in 1982 the following problem: IfP is a complete lattice, is Retr (P) a complete lattice? here Retr (P) denotes the set of all retraction operators onP with the pointwise order, that is,f≤g in Retr (P) ifff(x)≤g(x) for everyx inP. An affirmative answer will be given in the present paper. 相似文献