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201.
Riccardo Ghiloni 《Proceedings of the American Mathematical Society》2002,130(12):3525-3535
For each compact smooth manifold containing at least two points we prove the existence of a compact nonsingular algebraic set and a smooth map such that, for every rational diffeomorphism and for every diffeomorphism where and are compact nonsingular algebraic sets, we may fix a neighborhood of in which does not contain any regular rational map. Furthermore is not homotopic to any regular rational map. Bearing in mind the case in which is a compact nonsingular algebraic set with totally algebraic homology, the previous result establishes a clear distinction between the property of a smooth map to represent an algebraic unoriented bordism class and the property of to be homotopic to a regular rational map. Furthermore we have: every compact Nash submanifold of containing at least two points has not any tubular neighborhood with rational retraction.
202.
Vincent Blanloeil Osamu Saeki 《Transactions of the American Mathematical Society》2002,354(10):3955-3971
Consider a closed connected oriented 3-manifold embedded in the -sphere, which is called a -knot in this paper. For two such knots, we say that their Seifert forms are spin concordant, if they are algebraically concordant with respect to a diffeomorphism between the 3-manifolds which preserves their spin structures. Then we show that two simple fibered 3-knots are geometrically concordant if and only if they have spin concordant Seifert forms, provided that they have torsion free first homology groups. Some related results are also obtained.
203.
A. K. Ramazanov 《Mathematical Notes》1999,66(5):613-627
Suppose thatD={z:|z|<1}, L
2
(D) is the space of functions square-integrable over area inD,A
k
(D) is the set of allk-analytic functions inD, (A
1
(D)=A(D) is the set of all analytic functions inD),A
k
L
2
(D)=L
2
(D)∩A
k
(D),A
1
L
2
(D)=AL
2
(D),
. It is proved that the subspacesA
k
L
2
0
(D),k=1, 2,..., are orthogonal to one another and the spaceA
m
L
2
(D) is the direct sum of such subspaces fork=1, 2,...,m. The kernel of the orthogonal projection operator from the spaceA
m
L
2
(D) onto its subspacesA
k
L
2
0
(D) is obtained. These results are applied to the study of the properties of polyrational functions of best approximation in
the metricL
2
(D).
Translated fromMatematicheskie Zametki, Vol. 66, No. 5, pp. 741–759, November, 1999. 相似文献
204.
G. Min 《Journal of Approximation Theory》1999,98(2):197
This note characterizes the denseness of rational systems
in C[−1, 1], where the nonreal poles in {ak}∞k=1
\[−1, 1] are paired by complex conjugation. This extends an Achiezer's result. 相似文献
Full-size image
205.
We prove that if (,D) is a positivity preserving form on L
2
(E;m), and if (u
n)n is a sequence in D() converging m-almost everywhere to u L
2
(E;m), then (u,u) lim infn (u
n
,u
n
). 相似文献
206.
Time dependent problems in Partial Differential Equations (PDEs) are often solved by the Method Of Lines (MOL). For linear parabolic PDEs, the exact solution of the resulting system of first order Ordinary Differential Equations (ODEs) satisfies a recurrence relation involving the matrix exponential function. In this paper, we consider the development of a fourth order rational approximant to the matrix exponential function possessing real and distinct poles which, consequently, readily admits a partial fraction expansion, thereby allowing the distribution of the work in solving the corresponding linear algebraic systems in essentially Backward Euler-like solves on concurrent processors. The resulting parallel algorithm possesses appropriate stability properties, and is implemented on various parabolic PDEs from the literature including the forced heat equation and the advection-diffusion equation.Dedicated to Professor J. Crank on the occasion of his 80th birthday 相似文献
207.
Nine methods for expressing a proper rational function in terms of partial fractions are presented for the case where the denominator polynomial has been reduced to linear factors. Only those methods which are amenable to computation algorithms are considered. To the extent possible, Newton's divided difference formula is used to provide a uniform derivational tool. Each method is illustrated numerically. The efficiency of the methods are compared on the basis of the number of multiplications and divisions required in the computation. 相似文献
208.
The spectroscopic amplitudes, form factors, angular distributions and total cross-sections for two nucleon transfer reactions
in Zr-region in the zero range distorted wave Born approximation are calculated using consistent set of shell model wave functions.
A single normalisation factor gives a good fit to all the two neutron transfer reaction data whereas the corresponding fit
for the two-proton transfer reaction data is less satisfactory. 相似文献
209.
E.?Tomasi-GustafssonEmail author F.?Lacroix C.?Duterte G.?I.?Gakh 《The European Physical Journal A - Hadrons and Nuclei》2005,24(3):419-430
We perform a global analysis of the experimental data of the electromagnetic nucleon form factors, in space-like and time-like regions. We give the expressions of the observables in annihilation processes, such as p + ¯↦ℓ+ + ℓ-, ℓ = e or μ, in terms of form factors. We discuss some of the phenomenological models proposed in the literature for the space-like region, and consider their analytical continuation to the time-like region. After determining the parameters through a fit on the available data, we give predictions for the observables which will be experimentally accessible with large statistics, polarized annihilation reactions 相似文献
210.