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41.
42.
Bob Hoogenboom 《Arkiv f?r Matematik》1982,20(1):69-85
Proofs are given of two theorems of Berezin and Karpelevič, which as far as we know never have been proved correctly. By using
eigenfunctions of the Laplace-Beltrami operator it is shown that the spherical functions on a complex Grassmann manifold are
given by a determinant of certain hypergeometric functions. By application of this result, it is proved that a certain system
of operators, fow which explicit expressions are given, generates the algebra of radial parts of invariant differential operators. 相似文献
43.
Computable Homogeneous Boolean Algebras and a Metatheorem 总被引:1,自引:0,他引:1
P. E. Alaev 《Algebra and Logic》2004,43(2):73-87
We consider computable homogeneous Boolean algebras. Previously, countable homogeneous Boolean algebras have been described up to isomorphism and a simple criterion has been found for the existence of a strongly constructive (decidable) isomorphic copy for such. We propose a natural criterion for the existence of a constructive (computable) isomorphic copy. For this, a new hierarchy of
-computable functions and sets is introduced, which is more delicate than Feiner's. Also, a metatheorem is proved connecting computable Boolean algebras and their hyperarithmetical quotient algebras. 相似文献
44.
The N-heap Wythoffs game is a two-player impartial game with
N piles of tokens of sizes
Players take turns removing any number of tokens from a single pile, or removing
(a1,..., aN)
from all piles - ai tokens from the i-th pile,
providing that
where is the nim addition. The first player that cannot make a move loses. Denote all the
P-positions (i.e., losing positions) by
Two conjectures were proposed on the game by Fraenkel [7]. When
are fixed, i) there exists an integer N1
such that when
. ii) there exist integers N2
and _2 such that when
, the golden section.In this paper, we provide a sufficient condition for the conjectures to hold, and subsequently
prove them for the three-heap Wythoffs game with the first piles having up to 10 tokens.AMS Subject Classification: 91A46, 68R05. 相似文献
45.
A. L. Tukmakov 《Journal of Applied Mechanics and Technical Physics》2003,44(1):64-68
Synchronization of oscillations of thin elastic plates that are walls of a gasfilled channel is considered. The gas motion is described by a system of Navier–Stokes equations, which is solved using the secondorder MacCormack method with time splitting. The motion of the channel walls is described by a system of geometrically nonlinear dynamic equations of the theory of this plates, which is solved by the finitedifference method. Kinematic and dynamic contact conditions are imposed at the interface between the media. A numerical experiment is performed to determine typical dynamic regimes and study the transition of the aeroelastic system to inphase oscillations. 相似文献
46.
Fré dé ric Bayart 《Proceedings of the American Mathematical Society》2003,131(6):1789-1791
We study the composition operators which are similar to an isometry on the classical Hardy space .
47.
Referring to Tits alternative, we develop a necessary and sufficient condition to decide whether the normalizer of a finite group of integral matrices is polycyclic-by-finite or is containing a non-Abelian free group. This result is of fundamental importance to conclude whether the (outer) automorphism group of a Bieberbach group is polycyclic-by-finite or has a non-cyclic free subgroup. 相似文献
48.
L. J. Ratliff Jr. D. E. Rush Jr. 《Transactions of the American Mathematical Society》2000,352(4):1647-1674
The main theorem characterizes, in terms of bracket powers, analytic spread one ideals in local rings. Specifically, let be regular nonunits in a local (Noetherian) ring and assume that , the integral closure of , where . Then the main result shows that for all but finitely many units in that are non-congruent modulo and for all large integers and it holds that for and not divisible by , where is the -th bracket power of . And, conversely, if there exist positive integers , , and such that has a basis such that , then has analytic spread one.
49.
50.
We show that for any possible Weierstrass gap sequence L on a non-singular curve of genus 8 with twice the smallest positive non-gap is less than the largest gap there exists a pointed
non-singular curve (C, P) over an algebraically closed field of characteristic 0 such that the Weierstrass gap sequence at P is L. Combining this with the result in [6] we see that every possible Weierstrass gap sequence of genus 8 is attained by some
pointed non-singular curve.
*Partially supported by Grant-in-Aid for Scientific Research (17540046), Japan Society for the Promotion of Science.
**Partially supported by Grant-in-Aid for Scientific Research (17540030), Japan Society for the Promotion of Science. 相似文献