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961.
René Lamour 《Numerische Mathematik》1991,59(1):815-829
Summary Consider a TPBVP for transferable nonlinear DAE's. In general the shooting equation has a singular Jacobian. A multiple shooting method which has a nonsingular Jacobian and also produces consistent initial values for the integration is presented. The estimation of the condition of the Jacobian shows the well-posedness of the method. Some illustrative examples are given 相似文献
962.
963.
James M. Greenberg 《Journal of Differential Equations》2003,189(1):161-182
In this paper, we examine new “phase-field” models with semi-diffuse interfaces. These models have the property that the −1/+1 planar phase transitions take place over a finite interval. The models also support multiple interface solutions with interfaces centered at arbitrary points L1<L2<?<LN. These solutions correspond to local minima of an entropy functional (see (3.3) and (3.7)) rather than saddle points and are dynamically stable. The classical models have no such exact solutions but they do support solutions with N equally spaced transition points where the order parameter transitions between values pmin(N) and pmax(N) satisfying −1<pmin(N)<0<pmax(N)<1. These solutions of the classical model are saddle points of the entropy functional associated with those models and are not dynamically stable. 相似文献
964.
N. I. Chernov 《Probability Theory and Related Fields》1995,101(3):321-362
Summary We prove the central limit theorem and weak invariance principle for abstract dynamical systems based on bounds on their mixing coefficients. We also develop techniques of Markov approximations for dynamical systems. We apply our results to expanding interval maps, Axiom A diffeomorphisms, chaotic billiards and hyperbolic attractors. 相似文献
965.
Inmaculada Higueras 《BIT Numerical Mathematics》1994,34(3):361-366
Implicit Runge-Kutta (IRK) methods and projected IRK methods for the solution of semiexplicit index-2 systems of differential algebraic systems (DAEs) have been proposed by several authors. In this paper we prove that if a method satisfiesBA+A
t
B–bb
t
=0, it conserves quadratic invariants of DAEs. 相似文献
966.
Gerard J. Murphy 《Integral Equations and Operator Theory》1997,27(2):221-227
The class of Toeplitz algebras associated to ordered groups is important in the analysis of Toeplitz operators on the generalised Hardy spaces defined by such groups. The conditions under which these Toeplitz algebras are Type I C*-algebras are investigated. 相似文献
967.
To overcome known disadvantages in the use of singly-implicit methods in the solution of stiff differential equations, two
generalizations have been recently introduced. These are the use of additional diagonally-implicit stages and the use of effective
order as a weakening of the conditions on the method. In this paper, these two generalizations are combined into a unified
scheme. The resulting DESIRE methods are very promising alternatives to standard methods for solving stiff problems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
968.
Venkata Balaji Thiruvalloor Eesanaipaadi 《Journal of Pure and Applied Algebra》2007,208(1):237-259
We study degenerations of rank 3 quadratic forms and of rank 4 Azumaya algebras, and extend what is known for good forms and Azumaya algebras. By considering line-bundle-valued forms, we extend the theorem of Max-Albert Knus that the Witt-invariant—the even Clifford algebra of a form—suffices for classification. An algebra Zariski-locally the even Clifford algebra of a ternary form is so globally up to twisting by square roots of line bundles. The general, usual and special orthogonal groups of a form are determined in terms of automorphism groups of its Witt-invariant. Martin Kneser’s characteristic-free notion of semiregular form is used. 相似文献
969.
Kyusik Hong 《Journal of Pure and Applied Algebra》2007,208(1):361-369
We study when double covers of P3 ramified along nodal surfaces are not Q-factorial. In particular, we describe all the Q-factorial double covers of P3 ramified along quartic surfaces with at most seven simple double points and sextic surfaces with at most 16 simple double points. 相似文献
970.
We study the potential density of rational points on double solids ramified along singular reduced sextic surfaces. Also, we investigate elliptic fibration structures on nonsingular sextic double solids defined over a perfect field of characteristic 5. 相似文献