Distinguishing Contragredient Galois Representations in Characteristic Two
by
Darrin Doud
Brigham Young University

Recently, Ash, Pollack and Soares described Galois representations with image isomorphic to GL(3,2), and demonstrated computationally that these representations seem to be attached to arithmetic cohomology classes with predictable coefficient modules. However, in certain cases, they did not distinguish between two contragredient representations for which the predicted coefficient modules are different. We distinguish between these representations, and compare the results with arithmetic cohomology calculations to give additional evidence for a conjecture relating Galois representations to arithmetic cohomology.

Date received: March 30, 2005