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71.
We compute the 2-rank of the wild kernel WK2(F) of a number field by constructing a 2-class group ad hoc. The main result generalizes in the more intricate case the canonical isomorphism established for odd primes under the assumption in a previous article (cf. (Acta. Arith. 67 (1994) 335; Math. Z. 238 (2001) 335)). It involves a criterium of triviality for the 2-part of the wild kernel of Galois number fields and, in the particular case of quadratic fields, it leads to a logarithmic interpretation of the diophantine conditions obtained by other authors. 相似文献
72.
In the present paper we classify the conformally flat contact metric
manifolds of dimension
satisfying
.
We prove that these manifolds are Sasakian of constant curvature 1. 相似文献
73.
A method is proposed to find the digital input signals to enter in nonlinear acoustical systems (power amplifiers, transducers, etc.) in order to obtain desired arbitrary response signals. The searched input signals are found by performing a Monte Carlo search guided by a simulated annealing process applied to a hidden model with a small number of parameters. The physical system is actually used in the optimization procedure, in a real-time manner, so that no theoretical model of the system response is required. The main aspects of the algorithm are described and illustrated with several examples. 相似文献
74.
Roger?L.?JonesEmail author Joseph?M.?Rosenblatt Máté?Wierdl 《Israel Journal of Mathematics》2003,135(1):1-27
In this paper we continue our investigations of square function inequalities. The results in [9] are primarily one dimensional,
and here we extend all the results to multi-dimensional averages. Our basic tool is still a comparison of the ergodic averages
with various dyadic (reversed) martingales, but the Fourier transform arguments are replaced by more geometric almost orthogonality
arguments.
The results imply the pointwise ergodic theorem for the action of commuting measure preserving transformations, and give additional
information such as control of the number of upcrossings of the ergodic averages. Related differentiation results are also
discussed.
R. Jones is partially supported by NSF Grant DMS-9531526.
J. Rosenblatt is partially supported by NSF Grant DMS-9705228.
M. Wierdl is partially supported by NSF Grant DMS-9801602. 相似文献
75.
There are reverse inequalities for square functions of differences arising in ergodic theory and differentiation of functions.
For example, it is shown that if An is the usual average in ergodic theory, and (nk∶k=1,2,3,...) is an increasing lacunary sequence with no non-trivial common divisor, then one has for any p, 1<p<∞, there
is a constant Cp such that for all f∃ Lp(X),
. 相似文献
76.
77.
78.
Mathieu Florence 《Inventiones Mathematicae》2008,171(1):175-189
Let p be a prime number, let K be a field of characteristic not p, containing the p-th roots of unity, and let r≥1 be an integer. We compute the essential dimension of ℤ/p
r
ℤ over K (Theorem 4.1). In particular,
i) We have edℚ(ℤ/8ℤ)=4, a result which was conjectured by Buhler and Reichstein in 1995 (unpublished).
ii) We have edℚ(ℤ/p
r
ℤ)≥p
r-1. 相似文献
79.
80.