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991.
Let be a finite-dimensional hereditary algebra over a finite field k,
() and
() be, respectively, the Hall algebra and the composition algebra of ,
be the isomorphism classes of finite dimensional -modules and I the isomorphism classes of simple -modules. We define and , in
, to be the right and left derivations of
() respectively. By using these derivations and the action of the braid group on the set of exceptional sequences of -mod, we provide an effective algorithm of calculating the root vectors of real Schur roots. This means that we get an inductive method to express u as the combinations of elements ui in the Hall algebra, where i I and in
is any exceptional -module. Because of the canonical isomorphism between the Drinfeld–Jimbo quantum group and the generic composition algebra, our algorithm is applicable directly to quantum groups. In particular, all the root vectors are obtained in this way in the finite type cases. 相似文献
992.
It is proved that a Köthe sequence space is weakly orthogonal if and only if it is order continuous. Criteria for weak property () in Orlicz sequence spaces in the case of the Luxemburg norm as well as the Orlicz norm are given. 相似文献
993.
Doyle Britton Saliya A. deSilva Paul G. Gassman 《Journal of chemical crystallography》1999,29(8):949-953
Octahydroanthracenedicarbonitrile is monoclinic, space group P21/c, at 172 K, a = 4.723(7), b = 8.254(3), c = 16.190(7) Å, = 91.76(8)°, Z = 2, V = 630.8(12) Å3. The molecule, located on a center of symmetry, is disordered between the two senses of puckering in the aliphatic ring. The structure was also determined at 216, 256, and 297 K. The disorder increases with increasing temperature and can be described by a van't Hoff relationship with H = 5.2(3) kJ mol–1 and S = 13.8(12) J K–1 mol–1. 相似文献
994.
Multiplicative Difference Sets via Additive Characters 总被引:1,自引:0,他引:1
J. F. Dillon 《Designs, Codes and Cryptography》1999,17(1-3):225-235
We use Fourier analysis on the additive group of
to give an alternative proof of the recent theorem of Maschietti and to prove recent conjectures of No, Chung and Yun and No, Golomb, Gong, Lee and Gaal on difference sets in the multiplicative group of
, m odd. Along the ay e prove a stronger form of a celebrated theorem of Welch on the 3-valued cross-correlation of maximal length sequences. 相似文献
995.
996.
We establish local asymptotic normality of thinned empirical point processes, based on n i.i.d. random elements, if the probability
of thinning satisfies
. It turns out that the central sequence is determined by the limit of the coefficient of variation of the tangent function. The central sequence depends only on the total number
of nonthinned observations if and only if this limit is 1 or –1. In this case under suitable regularity conditions, an asymptotically efficient estimator of the underlying parameter can be based on
only. An application to density estimation leads to a fuzzy set density estimator, which is efficient in a parametric model. In a nonparametric setup, it can also outperform the usual kernel density estimator, depending on the values of the density and its second derivative. 相似文献
997.
We present a field-theoretic renormalization-group study for the critical behavior of a uniformly driven diffusive system with quenched disorder, which is modeled by different kinds of potential barriers between sites. Due to their symmetry properties, these different realizations of the random potential barriers lead to three different models for the phase transition to transverse order and to one model for the phase transition to longitudinal order all belonging to distinct universality classes. In these four models, which have different upper critical dimensions d
c, we find the critical scaling behavior of the vertex functions in spatial dimensions d<d
c. The deviation from purely diffusive behavior is characterized by the anomaly exponent , which we calculate at first and second order, respectively, in =d
c–d. In each model turns out to be positive, which means superdiffusive spread of density fluctuations in the driving force direction. 相似文献
998.
Anagnostopoulos K. N. Bialas P. Thorleifsson G. 《Journal of statistical physics》1999,94(3-4):321-345
We study with Monte Carlo methods an ensemble of c=–5 gravity graphs, generated by coupling a conformal field theory with central charge c=–5 to two-dimensional quantum gravity. We measure the fractal properties of the ensemble, such as the string susceptibility exponent
s and the intrinsic fractal dimension d
H. We find
s=–1.5(1) and d
H=3.36(4), in reasonable agreement with theoretical predictions. In addition, we study the critical behavior of an Ising model on a quenched ensemble of the c=–5 graphs and show that it agrees, within numerical accuracy, with theoretical predictions for the critical behavior of an Ising model coupled dynamically to two-dimensional quantum gravity, with a total central charge of the matter sector c=–5. 相似文献
999.
Vincent Borrelli Fabiano Brito Olga Gil-Medrano 《Annals of Global Analysis and Geometry》2003,23(2):129-140
We construct a one-parameter family of unit smooth vector fieldsglobally defined on the sphere
2k+1 for k 2, with energyconverging to the energy of the unit radial vector field, which isdefined on the complementary of two antipodal points. So we prove thatthe infimum of the energy of globally defined unit smooth vector fieldsis
相似文献
1000.
Suthep?SuantaiEmail author Chanan?Sudsukh 《Southeast Asian Bulletin of Mathematics》2003,26(2):337-350
In this paper, we give the matrix characterizations from any normal vector-valued FK-space containing ø(X) into scalar-valued sequence space c(q) and by applying this result, we also obtain necessary and sufficient conditions for infinite matrices mapping the sequence spaces
, and Fr(X, p) into the space c(q), where p = (Pk) and q = (qk) are bounded sequences of positive real numbers and r 0.AMS Subject Classification (2000): 46A45. 相似文献