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1.
Let ={e(u)|uI} be a one-parameter family of straight lines forming a ruledC r-2-surface E n (n2,r1) without singular generatorse(u) (uI). As a synopsis, a generalization and an improvement of various results already known about the strictional properties of ruled surfaces E n (especially in the casen=3) the author demonstrates a uniform geometrical way of defining and uniquely obtaining thestriction point S(u) and theparameter of distribution d(u) of a generatore(u) under the minimal assumptions thate(u)E n (n2) be noncylindrical andr1. Other methods of obtainingS(u) andd(u) are discussed in comparison, and special strictional properties ofskew ruled surfaces E n are proved.

Herrn Prof. Dr. H. R. Müller zum 65. Geburtstag  相似文献   

2.
It is known that the limit Area/Length for a sequence of convex sets expanding over the whole hyperbolic plane is less than or equal 1, and exactly 1 when the sets considered are convex with respect to horocycles. We consider geodesics and horocycles as particular cases of curves of constant geodesic curvature with 0 1 and we study the above limit Area/Length as a function of the parameter .  相似文献   

3.
This work is an attempt to give a complete survey of all known results about pseudo (v, k, )-designs. In doing this, the author hopes to bring more attention to his conjecture given in Section 6; an affirmative answer to this conjecture would settle completely the existence and construction problem for a pseudo (v, k, )-design in terms of the existence of an appropriate (v, k, )-design.  相似文献   

4.
We present a categorical characterization of term graphs (i.e., finite, directed acyclic graphs labeled over a signature) that parallels the well-known characterization of terms as arrows of the algebraic theory of a given signature (i.e., the free Cartesian category generated by it). In particular, we show that term graphs over a signature are one-to-one with the arrows of the free gs-monoidal category generated by . Such a category satisfies all the axioms for Cartesian categories but for the naturality of two transformations (the discharger ! and the duplicator ), providing in this way an abstract and clear relationship between terms and term graphs. In particular, the absence of the naturality of and ! has a precise interpretation in terms of explicit sharing and of loss of implicit garbage collection, respectively.  相似文献   

5.
Ohne Zusammenfassung Zusatz bei der Korrektur: Ein vollständiger und korrekter Beweis für die Entscheidbarkeit der eingangs angeführten Aanderaaschen Klasse ((0, ), (, , ...)) erscheint demnächst im JSL (S.O. Aanderaa/H.R.Lewis: Prefix classes of Krom formulas). Ebendort wird auch die Reduktionstypeneigenschaft für ((0, ), (0, 0, )) und ((0, )), (0, 0, )) nachgewiesen, während ((0, ), (, )) sich als entscheidbar herausgestellt hat (s. E. Börger: Eine entscheidbare Klasse von Kromformeln. ZMLG 19 (1973), 117–120.) Der Kromsche Reduktionstyp konnte mittlerweile einerseits zu ((0, ), (0, 4)) verschärft werden (s. D. Rödding, E. Börger: The undecidability of (0, 4)-formulae with binary disjunctions, vorgetragen auf dem Logic Coll. Bristol 1973, ein abstract erscheint im JSL), andererseits kündigt H.R.Lewis die Reduktionstypeneigenschaft für ((0, ), (0, 1)) an (s. H.R.Lewis: Krom formulas with one dyadic predicate letter. Notices AMS 20, 5 (1973) A-500, abstr. no. 73T-E78.)Dieser Aufsatz geht aus der Dissertation [2] hervor, die dem Fachbereich Mathematik der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Münster im Sommersemester 1971 vorgelegt worden ist. Die Ergebnisse stammen aus dem Wintersemester 1970/71. Eine Ankündigung der hauptsächlichen Resultate ist in den Notices of the American Mathematical Society 19, 2 (1972) A-333 unter der abstract no. * 72T-E24 erschienen.  相似文献   

6.
An association scheme is a combinatorial object derived from the orbitals of a transitive permutation group. Let G be a transitive permutation group acting on a finite set X. Then x XGx is a normal subgroup of G where Gx:={g G xg=x}. A meta-thin association scheme can be considered as a generalization of the situation where x XGx normalizes Gx. In this paper, we consider the automorphism group of a meta-thin association scheme, and obtain a sufficient condition for a meta-thin association scheme to have a transitive automorphism group. This enables us to conclude that every meta-thin association scheme with its thin residue isomorphic to the cyclic group of order pq, where p and q are primes, has a transitive automorphism group.  相似文献   

7.
Summary Consider the following quasilinear elliptic PDE, which is equivalent to a nonlinear variational inequality: –divF(u)+(u)f. Here is a singular maximal monotone graph and the nonlinear differential operator is only assumed to be monotone; surfaces of prescribed mean curvature over obstacles may thus be viewed as relevant examples. The numerical approximation proposed in this paper consists of combining continuous piecewise linear finite elements with a preliminary regularization of . The resulting scheme is shown to be quasi-optimally accurate inL . The underlying analysis makes use of both a topological technique and a sharpL p -duality argument.This work was partially supported by Consiglio Nazionale delle Ricerche of Italy while the author was in residence at the Istituto di Analisi Numerica del C.N.R. di Pavia  相似文献   

8.
f(x,y) 0BV(T2), ={1/n} n=1 .

Dedicated to Professor Károly Tandori, the outstanding mathematician and academician on his seventieth birthday

This work was done under the financial support of the Russian Foundation for Fundamental Scientific Research, Grant 93-01-00240.  相似文献   

9.
This paper deals with linear systems of difference equations whose coefficients admit generalized factorial series representations atz=. We are concerned with the behavior of solutions near the pointz= (the only fixed singularity for difference equations). It is important to know whether a system of linear difference equations has a regular singularity or an irregular singularity. To a given system () we can assign a number , called the Moser's invariant of (), so that the system is regular singular if and only if 1. We shall develop an algorithm, implementable in a computer algebra system, which reduces in a finite number of steps the system of difference equations to an irreducible form. The computation ot the number can be done explicitly from this irreducible form.  相似文献   

10.
Conditions are established when the collocation polynomials Pm(x) and PM(x), m M, constructed respectively using the system of nodes xj of multiplicities aj 1, j = O,, n, and the system of nodes x-r,,xo,,xn,,xn+r1, r O, r1 O, of multiplicities a-r,,(ao + yo),,(an + yn),,an+r1, aj + yj 1, are two sided-approximations of the function f on the intervals , xj[, j = O,...,n + 1, and on unions of any number of these intervals. In this case, the polynomials Pm (x), PM (l) (x) with l aj are two-sided approximations of the function f(1) in the neighborhood of the node xj and the integrals of the polynomials Pm(x), PM(x) over Dj are two-sided approximations of the integral of the function f (over Dj). If the multiplicities aj aj + yj of the nodes xj are even, then this is also true for integrals over the set j= µ k Dj µ 1, k n. It is shown that noncollocation polynomials (Fourier polynomials, etc.) do not have these properties.Kiev University. Translated from Vychislitel'naya i Prikladnaya Matematika, No. 67, pp. 31–37, 1989.  相似文献   

11.
Let {X t} t0 be a Feller process generated by a pseudo-differential operator whose symbol satisfiesÇn|q(Ç,)|c(1=)()) for some fixed continuous negative definite function (). The Hausdorff dimension of the set {X t:tE}, E [0, 1] is any analytic set, is a.s. bounded above by dim E. is the Blumenthal–Getoor upper index of the Levy Process associated with ().  相似文献   

12.
LetY = (X, {R i } oid) denote aP-polynomial association scheme. By a kite of lengthi (2 i d) inY, we mean a 4-tuplexyzu (x, y, z, u X) such that(x, y) R 1,(x, z) R 1,(y, z) R 1,(u, y) R i–1,(u, z) R i–1,(u, x) R i. Our main result in this paper is the following.  相似文献   

13.
In terms of hyperelliptic functions, we integrate a two-particle Hamiltonian with quartic potential and additional linear and nonpolynomial terms in the Liouville integrable cases 1:6:1 and 1:6:8.  相似文献   

14.
Two kinds of model composite materials with finely divided (1) crystal fillers—LiF or polyethylene-filled epoxy resin cured by polyethylenepolyamine — are investigated by X-ray diffractometry. It is found that tensile stresses arise in LiF crystals, which show a strong adhesion interaction with the binder, for all degrees of filling (from =2.2 to =74 vol.%) examined. Their values remain constant up to a degree of filling at which the boundary layers come into contact with one another. Then, the inner stresses decrease with increasing . In the crystalline regions of polyethylene, where the adhesion between the binder and crystals is weak, the inner stresses are compressive. It is shown that the thickness of the boundary layer of the matrix on the surface of filler particles can be evaluated by the method used.Institute of Polymer Mechanics, Latvian University, Riga, LV-1006 Latvia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 6, pp. 807–820, November–December, 1999.  相似文献   

15.
Summary Approximations for the function implicitly defined by (u)=(u, (u)) are obtained via the iterative scheme n(u)=(u, n–1(u)). In this paper the uniform convergence of high order derivatives of n to the corresponding derivatives of is proved. This result yields a high order approximation theorem for the input-output map generated by a nonlinear control system, using linear combinations of iterated integrals of the control.Lavoro eseguito nell'ambito del G.N.A.F.A. del C.N.R.  相似文献   

16.
We propose a manifestly invariant renormalization scheme for N=1 non-Abelian supersymmetric gauge theories.  相似文献   

17.
We analyze a novel twolevel queueing network with blocking, consisting of N level1 parallel queues linked to M level2 parallel queues. The processing of a customer by a level1 server requires additional services that are exclusively offered by level2 servers. These level2 servers are accessed through blocking and nonblocking messages issued by level1 servers. If a blocking message is issued, the level1 server gets blocked until the message is fully processed at the level2 server. The queueing network is analyzed approximately using a decomposition method, which can be viewed as a generalization of the wellknown twonode decomposition algorithm used to analyze tandem queueing networks with blocking. Numerical tests show that the algorithm has a good accuracy.  相似文献   

18.
f(x,y) jk . , {c jk} , f(x, )(, ) [0,1)х[0,1) , - (0,0). , , f, - f. , , , [1] . . - [5] [6].

This research is supported by National Science Council, Taipei, R.O.C. under Grant #NSC 84-2121-M-007-026.  相似文献   

19.
Combinatorial reasoning is applied to the analysis of two kinds of dynamic storage allocation system to derive results about the degree and characteristics of memory fragmentation. The simple first-fit scheme with immediate replacement, discussed by Knuth, is analyzed further, providinginter alia a new derivation of the fifty percent rule. Next a system with garbage collections is considered, and the mean and variance of the number of holes following a garbage collection are determined, along with other results. The cell distributions resulting from these two idealized policies are contrasted.This research was supported in part by the National Science and Engineering Research Council of Canada under an operating grant.  相似文献   

20.
For fixed positive integersab, natural numbersl 1k 1,l 2k 2 andn, denote withd a,b (l 1,k 1;l 2,k 2;n) the number of all (,)N2 with a b =n,l 1(modk 1),l 2(modk 2). In the present paper we establish asymptotic formulas for the Dirichlet summatory function ofd a,b (l 1,k 1;l 2,k 2;n) with both upper and lower estimates of the error term, all of them uniform in the moduli.  相似文献   

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