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151.
Michael Bildhauer 《manuscripta mathematica》1998,97(3):389-406
H?lder continuity up to the free boundary is proved for minimizing solutions if they meet the supporting surface in an angle
which is bounded away from zero. The problem is localized by proving the continuity of the distance function, a result which
is also true for stationary points.
Received: 14 April 1998 相似文献
152.
Michael A. Zazanis 《Queueing Systems》1992,11(4):419-428
We examine level crossings of sample paths of queueing processes and investigate the conditions under which the limiting empirical distribution for the workload process exists and is absolutely continuous. The connection between the density of the workload distribution and the rate of downcrossings is established as a sample path result that does not depend on any stochastic assumptions. As a corollary, we obtain the sample path version of the Takács formula connecting the time and customer stationary distributions in a queue. Defective limiting empirical distributions are considered and an expression for the mass at infinity is derived.This research has been supported in part by NSF Grants ECS-8811003 and DDM-8905638. 相似文献
153.
Michael R. Matthews 《School science and mathematics》1998,98(6):285-293
Based on the forthcoming book, Time for Science Education ( Matthews, in press ), this article notes that the US National Science Education Standards advocate liberal, contextual, or cultural goals for science education, including the expectation that students will understand a certain amount of the historical and cultural significance of science. After mentioning something of the rich role played by the pendulum in the foundation of modern science, in solving the longitude problem, in establishing a universal length standard, and in allowing the creation of an accurate timekeeper, as well as the pendulum clock's function in philosophy and theology, the article draws attention to the scant treatment given the pendulum in the Standards. Opportunities are thus lost for realizing the Standards' laudable goals for US science education. Finally, it is claimed that realizing these cultural goals for science education requires more routine incorporation of the history and philosophy of science into preservice and inservice courses for science teachers. 相似文献
154.
Andrew V. Goldberg Michael D. Grigoriadis Robert E. Tarjan 《Mathematical Programming》1991,50(1-3):277-290
Goldfarb and Hao (1990) have proposed a pivot rule for the primal network simplex algorithm that will solve a maximum flow problem on ann-vertex,m-arc network in at mostnm pivots and O(n
2
m) time. In this paper we describe how to extend the dynamic tree data structure of Sleator and Tarjan (1983, 1985) to reduce the running time of this algorithm to O(nm logn). This bound is less than a logarithmic factor larger than those of the fastest known algorithms for the problem. Our extension of dynamic trees is interesting in its own right and may well have additional applications.Research partially supported by a Presidential Young Investigator Award from the National Science Foundation, Grant No. CCR-8858097, an IBM Faculty Development Award, and AT&T Bell Laboratories.Research partially supported by the Office of Naval Research, Contract No. N00014-87-K-0467.Research partially supported by the National Science Foundation, Grant No. DCR-8605961, and the Office of Naval Research, Contract No. N00014-87-K-0467. 相似文献
155.
156.
157.
A semigroup S is called collapsing if there exists a positiveinteger n such that for every subset of n elements in S, atleast two distinct words of length n on these letters are equalin S. In particular, S is collapsing whenever it satisfies alaw. Let U(A) denote the group of units of a unitary associativealgebra A over a field k of characteristic zero. If A is generatedby its nilpotent elements, then the following conditions areequivalent: U(A) is collapsing; U(A) satisfies some semigrouplaw; U(A) satisfies the Engel condition; U(A) is nilpotent;A is nilpotent when considered as a Lie algebra. 相似文献
158.
159.
We study the renormalization group for nearly marginal perturbations of a minimal conformal field theory Mp with p 1. To leading order in perturbation theory, we find a unique one-parameter family of “hopping trajectories” that is characterized by a staircase-like renormalization group flow of the C-function and the anomalous dimensions and that is related to a factorizable scattering theory recently solved by Al. B. Zamolodchikov. We argue that this system is described by interactions of the form
. As a function of the relevant parameter t, it undergoes a phase transition with new critical exponents simultaneously governed by all fixed points Mp, Mp−1,…, M3. Integrable lattice models represent different phases of the same integrable system that are distinguished by the sign of the irrelevant parameter
. 相似文献
160.
The Nd:YAG laser-induced breakdown of 20 μm glass microspheres was investigated using time-resolved optical shadow and Schlieren images. Time-resolved imaging showed the location of the initial breakdown and the shockwave motion over its first 400 μm of expansion. Measured shockwave velocities were in the range of 1–10 km/s and showed a linear dependency on laser fluence within 30 ns. 相似文献