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1.
We study the moduli scheme M(2;0,n) of rank-2 stable vector bundles with Chern classes c 1=0, c 2=n, on the Fano threefold X – the double space P 3 of index two. New component of this scheme is produced via the Serre construction using certain families of curves on X. In particular, we show that the Abel–Jacobi map :HJ(X) of any irreducible component H of the Hilbert scheme of X containing smooth elliptic quintics on X into the intermediate Jacobian J(X) of X factors by Stein through the quasi-finite (probably birational) map g:M of (an open part of) a component M of the scheme M(2;0,3) to a translate of the theta-divisor of J(X).  相似文献   
2.
3.
描述了秩为3的Jacobian的性质,探讨了应用Mathematica软件及秩为3的Jacobian来研究单组分、单相系统热力学一阶偏微商和二阶偏微商的方法.  相似文献   
4.
    
The harmonic balance (HB) method is utilized to obtain the periodic solutions for the two-dimensional airfoil with cubic nonlinearity in pitch undergoing subsonic flow. In the course of formulating the HB algebraic system, the manipulation software Mathematica is employed to deal with the complex Fourier coefficients involved with the nonlinear term. In general, to solve the HB algebraic system, either a symbolic calculation or a numerical approximation of the Jacobian matrix is required in each iteration, which is computationally expensive. To remedy this drawback, the Jacobian matrix is explicitly derived in this paper. The effects of exploiting the explicit Jacobian matrix on the accuracy and efficiency of the HB method are investigated, through comparing with the case using a numerical Jacobian matrix calculated by a three-point difference technique. Moreover, the spectral analysis is applied to the periodic motions by the numerical method to provide insight into the distribution of the dominant frequencies, so as to provide a reasonable suggestion for the truncation of the Fourier series expansion in the HB method. In addition, a frequency modulation phenomenon is identified in the pitch motions via spectral analysis, whose effect on the accuracy of the HB method is examined both numerically and analytically. Finally, illustrative examples validate that the HB method with as many harmonics as the spectral analysis suggests can yield sufficiently accurate solutions.  相似文献   
5.
In this paper, we show the existence of Landau constant for functions with logharmonic Laplacian of the form F(z) = ∣z2L(z) + K(z), ∣z∣ < 1, where L is logharmonic and K is harmonic. Moreover, the problem of minimizing the area is solved  相似文献   
6.
本文利用常微方程系统二维重构变换的雅可比行列式,对强迫Brusselator吸引子进行了分框计算,确定出二维重构的延迟时间.  相似文献   
7.
A new version of finite difference approximation of the generalized Jacobian for a finite max function is constructed. Numerical results are reported for the generalized Newton methods using this approximation.  相似文献   
8.
Let X 1, ..., X m denote smooth projective curves of genus g i ≥ 2 over an algebraically closed field of characteristic 0 and let n denote any integer at least equal to . We show that the product JX 1 × ... × JX m of the corresponding Jacobian varieties admits the structure of a Prym-Tyurin variety of exponent n m-1. This exponent is considerably smaller than the exponent of the structure of a Prym-Tyurin variety known to exist for an arbitrary principally polarized abelian variety. Moreover it is given by explicit correspondences.   相似文献   
9.
We construct planar bi-Sobolev mappings whose local volume distortion is bounded from below by a given function fLp with p>1. More precisely, for any 1<q<(p+1)/2 we construct W1,q-bi-Sobolev maps with identity boundary conditions; for fL, we provide bi-Lipschitz maps. The basic building block of our construction are bi-Lipschitz maps which stretch a given compact subset of the unit square by a given factor while preserving the boundary. The construction of these stretching maps relies on a slight strengthening of the celebrated covering result of Alberti, Csörnyei, and Preiss for measurable planar sets in the case of compact sets. We apply our result to a model functional in nonlinear elasticity, the integrand of which features fast blowup as the Jacobian determinant of the deformation becomes small. For such functionals, the derivation of the equilibrium equations for minimizers requires an additional regularization of test functions, which our maps provide.  相似文献   
10.
Let k,n2 be integers. A generalized Fermat curve of type (k,n) is a compact Riemann surface S that admits a subgroup of conformal automorphisms HAut(S) isomorphic to Zkn, such that the quotient surface S/H is biholomorphic to the Riemann sphere C? and has n+1 branch points, each one of order k. There exists a good algebraic model for these objects, which makes them easier to study. Using tools from algebraic topology and integration theory on Riemann surfaces, we find a set of generators for the first homology group of a generalized Fermat curve. Finally, with this information, we find a set of generators for the period lattice of the associated Jacobian variety.  相似文献   
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