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91.
92.
93.
Consider a finite dimensional vector space over a field of prime characteristic. We show that two differently constructed
filtrations of the symmetric powers of this space coincide. One of them arises from the representation theory of the general
linear group. In order to get the other one we interpret the symmetric powers as crystalline cohomology groups and use the
action of the Frobenius endomorphism on this cohomology.
Dedicated to Jacques Tits on his sixtieth birthday
Supported in part by the NSF. 相似文献
94.
95.
Hexa‐ and nonanuclear titanium complexes were obtained by self‐assembly of titanium(IV)‐tert‐butoxide and D ‐mandelic acid. Suitable single crystals of these complexes were characterized by X‐ray structure analysis. When used with these complexes, aldol adducts were isolated with a high degree of regioselectivity in direct aldol additions of aromatic and aliphatic aldehydes to functionalized unsymmetrical ketones. High syn‐diastereoselectivities were obtained in aldol additions of enolizable aldehydes with hydroxyacetone and methoxyacetone. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
96.
97.
98.
John N. Helbert Edward H. Poindexter Burkhard E. Wagner 《Chemical physics letters》1977,52(3):546-548
Strongly scalar 1H intermolecular dynamic nuclear polarization (DNP) of solvent 1H nuclei in solutions of organic free radicals has now been observed at room temperature. Transient protonation of the CF3COOH/pyridyl imidazoline-1-oxyl radical system accounts for the observed effects. 相似文献
99.
Burkhard Wald 《manuscripta mathematica》1983,42(2-3):297-309
P(I) denotes the abelian group of integer-valuated functions defined on the set I, Pκ (I) its subgroup consisting of all elements, which support has size less than the infinite cardinal κ and Qκ (I) the quotient P(I)/Pκ(I). We formulate a statement I(κ) in the following way: For an arbitrary set I you can lift every homomorphism from P (?) to Qκ(I) to a homomorphism from P(?) to P(I). Using Martin's Axiom we show, that L(?) is independent of ZFC. 相似文献
100.
Ronald D Brown Peter D Godfrey Burkhard Kleibömer 《Journal of Molecular Spectroscopy》1985,114(2):257-273
An extensive study of the microwave spectrum of cyanamide has been undertaken, the analysis being based in part on semirigidbender calculations by the methods of Bunker and Szalay. Inversion lines of NH2CN, branches and a number of vibrational satellites of the J = 2?1 transition were observed. A two-vibrational-state Hamiltonian was used to fit simultaneously the 0+ and 0? microwave data and yielded rotational constants X, Y, Z, DJ, DJK, d1, HJK as well as the inversion splitting and the μyz-connecting matrix element. Vibrational satellite data of seven isotopic species and infrared frequencies of NH2CN were included in the semirigid bender calculations: The NCN spine is nonlinear by ca. 5° in the equilibrium structure of the molecule. Also, ; <HNH/2 = 60.39° ? 0.1134?2; (? is the inversion angle in rad); fixed. The inclusion of the NC bond flexing was necessary in order to reproduce the observed vibrational satellite patterns of NH2CN, NHDCN, and ND2CN. The barrier to inversion of the amino group is 510 ± 6 cm?1 with minima at ±45.0 ±0.2°. The inversion dipole moment is 0.91 ± 0.02 Debye. 相似文献