Current Topics Seminar


Speaker Robert Miller
Title The PHS Method for Elliptic Curves
Date May 7 4:00pm PDL C-36
An elliptic curve (over Q) is a cubic algebraic curve with a group law. One way of studying the arithmetic of an elliptic curve E is by studying its Weil-Châtelet group. This is the set of principal homogeneous spaces (PHS) C/E, which are curves which act on the elliptic curve in a simply transitive, algebraic way. Of particular interest are the elements of the Weil-Châtelet group which possess points defined over every localization Qp and R, and yet are insoluble over Q (even though the converse is always true, this can and does happen). These form the Shafarevich-Tate group, a group whose finiteness is not known in general, but whose order is conjecturally given in all cases by Birch and Swinnterton-Dyer. PHS computations can be used to verify this conjecture in many specific cases.