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161.
The paper is for a general audience and may serve as a preliminary introduction to the theory of finite-type invariants. 相似文献
162.
163.
In two dimensions, we prove the existence of a domain
minimizing the buckling load of a clamped plate among all domains
of given measure. In order to prove that the optimal set is the
disk, we discuss possible ways of applying an idea of Willms and
Weinberger if the regularity of the optimal set is not a priori
assumed. 相似文献
164.
We present here an improved version of the method introduced by the first author to derive
pointwise gradient estimates for the solutions of one-dimensional parabolic problems. After considering
a general qualinear equation in divergence form we apply the method to the case of a nonlinear
diffusion-convection equation. The conclusions are stated first for classical solutions and then for
generalized and mild solutions. In the case of unbounded initial datum we obtain several regularizing
effects for t > 0. Some unilateral pointwise gradient
estimates are also obtained. The case of
the Dirichlet problem is also considered. Finally, we collect, in the last section, several comments
showing the connections among these estimates and the study of the free boundaries
associated to the solutions of the diffusion-convection equation. 相似文献
165.
Guohua Peng 《Journal of Number Theory》2003,98(2):221-227
In this paper, we give a definition of genus field of function field with one variable over finite fields. And we explicitly describe the genus fields of Kummer function fields. For quadratic function fields case, our results are analogous to the genus fields of quadratic number fields. 相似文献
166.
We consider the support problem of Erdös in the context of l-adic representations of the absolute Galois group of a number field. Main applications of the results of the paper concern Galois cohomology of the Tate module of abelian varieties with real and complex multiplications, the algebraic K-theory groups of number fields and the integral homology of the general linear group of rings of integers. We answer the question of Corrales-Rodrigáñez and Schoof concerning the support problem for higher dimensional abelian varieties. 相似文献
167.
168.
We discuss growth rates of Betti numbers in a family of coverings of a compact cell complex X, when the corresponding L2 Betti number of X is zero. We show that the Betti numbers are bounded by a function, sub-linear in the order of the covering. If the appropriate Novikov-Shubin invariant of X is positive, the rate bounds are improved. For well behaved families (such as congruence covers of symmetric spaces), if the L2 spectrum of X? has a gap at zero then the growth rate is bounded by the order of the covering raised to a power less than one. 相似文献
169.
Two multivariate hazard rate stochastic orders are introduced and studied. Their meaning, properties, and relationship to other common stochastic orders are examined and investigated. Some examples that illustrate the theory are detailed. Finally, some applications of the new orders in reliability theory and in actuarial science are described. 相似文献
170.