5,357 research outputs found
The support problem for abelian varieties
Let be an abelian variety over a number field . If and are
-rational points of such that the order of the reduction of divides
that of for all but finitely many primes of the ring of integers of ,
then there exists a -endomorphism of and a positive integer
such that .Comment: 7 pages, plain TeX. The statements of the main theorem and main
corollary are slightly weakened to coincide with what is actually proved in
the paper. There are a few other minor changes. To appear in the Journal of
Number Theor
How often is a permutation an n'th power?
We give a short argument that for any fixed n, the probability that a
permutation on m letters is an n'th power is asymptotically C m^{phi(n)/n - 1}.Comment: 2 page
An Experiment with Hierarchical Bayesian Record Linkage
In record linkage (RL), or exact file matching, the goal is to identify the
links between entities with information on two or more files. RL is an
important activity in areas including counting the population, enhancing survey
frames and data, and conducting epidemiological and follow-up studies. RL is
challenging when files are very large, no accurate personal identification (ID)
number is present on all files for all units, and some information is recorded
with error. Without an unique ID number one must rely on comparisons of names,
addresses, dates, and other information to find the links. Latent class models
can be used to automatically score the value of information for determining
match status. Data for fitting models come from comparisons made within groups
of units that pass initial file blocking requirements. Data distributions can
vary across blocks. This article examines the use of prior information and
hierarchical latent class models in the context of RL.Comment: 14 pages, 0 figure
Discussion of "Calibrated Bayes, for Statistics in General, and Missing Data in Particular" by R. J. A. Little
Discussion of "Calibrated Bayes, for Statistics in General, and Missing Data
in Particular" by R. Little [arXiv:1108.1917]Comment: Published in at http://dx.doi.org/10.1214/10-STS318B the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Beauville surfaces and finite simple groups
A Beauville surface is a rigid complex surface of the form (C1 x C2)/G, where
C1 and C2 are non-singular, projective, higher genus curves, and G is a finite
group acting freely on the product. Bauer, Catanese, and Grunewald conjectured
that every finite simple group G, with the exception of A5, gives rise to such
a surface. We prove that this is so for almost all finite simple groups (i.e.,
with at most finitely many exceptions). The proof makes use of the structure
theory of finite simple groups, probability theory, and character estimates.Comment: 20 page
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