Hilbert symbols, class groups and quaternion algebras
Let be a quaternion algebra over a number field . To a pair of Hilbert symbols and for we associate an invariant in a quotient of the narrow ideal class group of . This invariant arises from the study of finite subgroups of maximal arithmetic kleinian groups. It measures the distance between orders and in associated to and If , we compute by means of arithmetic in the field The problem of extending this algorithm to the general case leads to studying a finite graph associated...