8,218 research outputs found
Integer Points in Backward Orbits
A theorem of J. Silverman states that a forward orbit of a rational map
on contains finitely many -integers in the number
field when is not a polynomial. We state an analogous
conjecture for the backward orbits using a general -integrality notion based
on the Galois conjugates of points. This conjecture is proven for the map
, and consequently Chebyshev polynomials, by uniformly bounding
the number of Galois orbits for when is a non-root
of unity. In general, our conjecture is true provided that the number of Galois
orbits for is bounded independently of .Comment: 13 page
Towards Evaluating the Quality of a Spreadsheet: The Case of the Analytical Spreadsheet Model
We consider the challenge of creating guidelines to evaluate the quality of a
spreadsheet model. We suggest four principles. First, state the domain-the
spreadsheets to which the guidelines apply. Second, distinguish between the
process by which a spreadsheet is constructed from the resulting spreadsheet
artifact. Third, guidelines should be written in terms of the artifact,
independent of the process. Fourth, the meaning of "quality" must be defined.
We illustrate these principles with an example. We define the domain of
"analytical spreadsheet models", which are used in business, finance,
engineering, and science. We propose for discussion a framework and terminology
for evaluating the quality of analytical spreadsheet models. This framework
categorizes and generalizes the findings of previous work on the more narrow
domain of financial spreadsheet models. We suggest that the ultimate goal is a
set of guidelines for an evaluator, and a checklist for a developer.Comment: Proc. European Spreadsheet Risks Int. Grp. (EuSpRIG) 2011 ISBN
978-0-9566256-9-
- ā¦