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131.
We consider first the initial-boundary value problem for the parabolic equation
相似文献
132.
Martin H. Gutknecht 《Numerische Mathematik》1989,56(6):547-589
Summary We discuss first the block structure of the Newton-Padé table (or, rational interpolation table) corresponding to the double sequence of rational interpolants for the data{(z
k, h(zk)}
k
=0. (The (m, n)-entry of this table is the rational function of type (m,n) solving the linearized rational interpolation problem on the firstm+n+1 data.) We then construct continued fractions that are associated with either a diagonal or two adjacent diagonals of this Newton-Padé table in such a way that the convergents of the continued fractions are equal to the distinct entries on this diagonal or this pair of diagonals, respectively. The resulting continued fractions are generalizations of Thiele fractions and of Magnus'sP-fractions. A discussion of an some new results on related algorithms of Werner and Graves-Morris and Hopkins are also given.Dedicated to the memory of Helmut Werner (1931–1985) 相似文献
133.
We study the linear system =Ax+Bu from a differential geometric point of view. It is well-known that controllability of the system is related to the one-parameter family of operators et
B. We use this to give a proof of the classical controllability conditions in terms of the differential geometry of certain curves in n. We then view (t)=Im(et
B) as a curve in appropriate Grassmannian and see that, in local coordinates, is an integral curve of the flow induced by a matrix Riccati equation. We obtain qualitative geometric conditions on that are equivalent to the controllability of the system. To get quantitiative results, we lift to a curve l' in a splitting space, a generalized Grassmannian, which has the advantage of being a reductive homogeneous space of the general linear group, GL(n). Explicit and simple expressions concerning the geometry of are computed in terms of the Lie algebra of GL(n), and these are related to the controllability of the system.James Wolper was a visiting professor in the Department of Mathematics at Texas Tech University while much of this research was conducted. He would like to express appreciation for the hospitality he received during his visit. 相似文献
134.
Andrea Laforgia Martin E. Muldoon 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1988,39(2):267-271
Summary We show, among other things, that the positive zeros of a solution ofy
+x
y=0,y(0)=0 decrease to 1 as increases, 0.
Sommario Si dimostra, tra l'altro, che gli zeri positivi d'una soiuzione diy +x y=0,y(0)=0 decrescono al limite 1, quando cresce, 0. To the memory of Milo Háik This research was supported by grants from the Natural Sciences and Engineering Research Council (Canada) and Consiglio Nazionale delle Ricerche (Italy). Some of the work was done while the second-named author was visiting the Department of Mathematics, University of Torino. 相似文献 135.
Martin Charles Golumbic 《Graphs and Combinatorics》1988,4(1):307-321
Let be a family of sets. The intersection graph of is obtained by representing each set in by a vertex and connecting two vertices by an edge if and only if their corresponding sets intersect. Of primary interest are those classes of intersection graphs of families of sets having some specific topological or other structure. The grandfather of all intersection graphs is the class of interval graphs, that is, the intersection graphs of intervals on a line.The scope of research that has been going on in this general area extends from the mathematical and algorithmic properties of intersection graphs, to their generalizations and graph parameters motivated by them. In addition, many real-world applications involve the solution of problems on such graphs.In this paper a number of topics in algorithmic combinatorics which involve intersection graphs and their representative families of sets are presented. Recent applications to computer science are also discussed. The intention of this presentation is to provide an understanding of the main research directions which have been investigated and to suggest possible new directions of research. 相似文献
136.
137.
138.
Anjos JC Appel JA Bean A Bracker SB Browder TE Cremaldi LM Elliott JR Escobar CO Estabrooks P Gibney MC Hartner GF Karchin PE Kumar BR Losty MJ Luste GJ Mantsch PM Martin JF McHugh S Menary SR Morrison RJ Nash T Nauenberg U Ong P Pinfold J Punkar G Purohit MV Raab JR Santoro AF Sidhu JS Sliwa K Sokoloff MD Souza MH Spalding WJ Streetman ME Stundia AB Witherell MS 《Physical review letters》1988,60(14):1379-1381
139.
140.
R. Kleiss A. D. Martin W. J. Stirling 《Zeitschrift fur Physik C Particles and Fields》1988,39(3):393-398
We study means of identifying top quarks of mass in the range 70–120 GeV at the CERN and FNAL \(\bar pp\) colliders. We show that “W+dijet” production presents a serious background to the conventional “isolated electron+dijet” signature of top. We study an improved signature, calculate the expected event rates, and discuss the determination of the mass of the top quark. 相似文献
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