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141.
Two improvements for the algorithm of Breiman and Cutler are presented. Better envelopes can be built up using positive quadratic forms. Better utilization of first and second derivative information is attained by combining both global aspects of curvature and local aspects near the global optimum. The basis of the results is the geometric viewpoint developed by the first author and can be applied to a number of covering type methods. Improvements in convergence rates are demonstrated empirically on standard test functions.Partially supported by an University of Canterbury Erskine grant. 相似文献
142.
143.
Impacs - A bus crew scheduling system using integer programming 总被引:1,自引:0,他引:1
Barbara M. Smith 《Mathematical Programming》1988,42(1-3):181-187
144.
145.
Using the continuum hypothesis, Sierpinski constructed a nonmeasurable function such that is countable for every Clearly, such a function is symmetrically approximately continuous everywhere.
Here we to show that Sierpinski's example cannot be constructed in ZFC. Moreover, we show it is consistent with ZFC that if a function is symmetrically approximately continuous almost everywhere, then it is measurable.
146.
Károly Böröczky Jr. Ildikó Fábián Gergely Wintsche 《Periodica Mathematica Hungarica》2006,53(1-2):103-113
Summary We determine the minimal radius of <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource
Format="TEX"><![CDATA[<InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"4"><EquationSource
Format="TEX"><![CDATA[<InlineEquation ID=IE"5"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>n=2$,
$d$ or $2d$ congruent balls,
which cover the $d$-dimensional crosspolytope. 相似文献
147.
Károly Bezdek 《Periodica Mathematica Hungarica》2006,53(1-2):59-69
Summary The Illumination Conjecture was raised independently by Boltyanski and
Hadwiger in 1960. According to this conjecture any <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation
ID=IE"2"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>d$-dimensional
convex body
can be illuminated by at most $2^d$ light sources. This is an important
fundamental problem. The paper surveys the state of the art of the Illumination
Conjecture. 相似文献
148.
It is well known that Universal cycles (U-cycles) of k-letter words on an n-letter alphabet exist for all k and n. In this paper, we prove that Universal cycles exist for several restricted classes of words, including non-bijections, “equitable” words (under suitable restrictions), ranked permutations, and “passwords”. In each case, proving the connectedness of the underlying de Bruijn digraph is a non-trivial step. 相似文献
149.
N. Tsirivas 《Mathematische Nachrichten》2010,283(6):909-920
We show that, if individual universal series exist, then we can choose a sequence of universal series performing simultaneous universal approximation with the same sequence of indices. As an application we derive the existence of universal Laurent Series on an annulus using only the existence of universal Taylor Series on discs. Our results are generic (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
150.
Hirobumi Mizuno 《Discrete Mathematics》2006,306(2):220-230
We give a decomposition formula for the Bartholdi zeta function of a graph G which is partitioned into some irregular coverings. As a corollary, we obtain a decomposition formula for the Bartholdi zeta function of G which is partitioned into some regular coverings. 相似文献