30,550 research outputs found
The Maximal Rank of Elliptic Delsarte Surfaces
Shioda described in his article from 1986 a method to compute the Lefschetz
number of a Delsarte surface. In one of his examples he uses this method to
compute the rank of an elliptic curve over k(t). In this article we find all
elliptic curves over k(t) for which his method is applicable. For each of these
curves we also compute the Mordell-Weil rank
Enron versus EUSES: A Comparison of Two Spreadsheet Corpora
Spreadsheets are widely used within companies and often form the basis for
business decisions. Numerous cases are known where incorrect information in
spreadsheets has lead to incorrect decisions. Such cases underline the
relevance of research on the professional use of spreadsheets.
Recently a new dataset became available for research, containing over 15.000
business spreadsheets that were extracted from the Enron E-mail Archive. With
this dataset, we 1) aim to obtain a thorough understanding of the
characteristics of spreadsheets used within companies, and 2) compare the
characteristics of the Enron spreadsheets with the EUSES corpus which is the
existing state of the art set of spreadsheets that is frequently used in
spreadsheet studies.
Our analysis shows that 1) the majority of spreadsheets are not large in
terms of worksheets and formulas, do not have a high degree of coupling, and
their formulas are relatively simple; 2) the spreadsheets from the EUSES corpus
are, with respect to the measured characteristics, quite similar to the Enron
spreadsheets.Comment: In Proceedings of the 2nd Workshop on Software Engineering Methods in
Spreadsheet
Quantitative estimates and extrapolation for multilinear weight classes
In this paper we prove a quantitative multilinear limited range extrapolation
theorem which allows us to extrapolate from weighted estimates that include the
cases where some of the exponents are infinite. This extends the recent
extrapolation result of Li, Martell, and Ombrosi. We also obtain vector-valued
estimates including spaces and, in particular, we are able to
reprove all the vector-valued bounds for the bilinear Hilbert transform
obtained through the helicoidal method of Benea and Muscalu. Moreover, our
result is quantitative and, in particular, allows us to extend quantitative
estimates obtained from sparse domination in the Banach space setting to the
quasi-Banach space setting.
Our proof does not rely on any off-diagonal extrapolation results and we
develop a multilinear version of the Rubio de Francia algorithm adapted to the
multisublinear Hardy-Littlewood maximal operator.
As a corollary, we obtain multilinear extrapolation results for some upper
and lower endpoints estimates in weak-type and BMO spaces.Comment: 44 pages. Minor improvements. To appear in Mathematische Annale
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