Bianca Viray
Computing Automorphism Groups of Rational Functions.
Втр, 02/28/2012 - 15:01 — SomNambulAuthors: Bianca Viray, Xander Faber, Michelle Manes
Subjects: Number Theory
AbstractLet phi be an endomorphism of the projective line of degree at least 2,
defined over a noetherian commutative ring R with unity. We show that the
automorphism group of phi is a finite group scheme, and we construct algorithms
to compute it when R is a finite field or a number field. We also give an
algorithm for determining when two such endomorphisms are conjugate. We have
implemented these algorithms in Sage when R is a finite field or the field of
rational numbers.Transcendental Brauer elements via descent on elliptic surfaces.
Пнд, 02/27/2012 - 15:01 — SomNambulAuthors: Bianca Viray
Subjects: Algebraic Geometry
AbstractTranscendental Brauer elements are notoriously difficult to compute. Work of
Wittenberg, and later, Ieronymou, gives a method for computing 2-torsion
transcendental classes on surfaces that have a genus 1 fibration with rational
2-torsion in the Jacobian fibration. We use ideas from a descent paper of
Poonen and Schaefer to remove this assumption on the rational 2-torsion.- 1 комментарий
- login or register to post comments
A family of varieties with exactly one pointless rational fiber.
Втр, 09/01/2009 - 12:47 — SomNambulAuthors: Bianca Viray
Subjects: Number Theory
AbstractWe construct a concrete example of a 1-parameter family of smooth projective
geometrically integral varieties over an open subscheme of P^1_Q such that
there is exactly one rational fiber with no rational points. This makes
explicit a construction of Poonen.
Вход в систему
