16/05/2013, 16:30 — 17:30 — Room P3.10, Mathematics Building
Sérgio Mendes, Instituto Universitário de Lisboa, ISCTE-IUL
Noncommutative summands of the -algebra
Let denote the Laurent series in the
indeterminate with coefficients over the finite field with
two elements . This is a local nonarchimedean field
with characteristic . We show that the structure of the reduced
group -algebra of is determined
by the arithmetic of the ground field. Specifically, the algebra
has countably many
noncommutative summands, induced by the Artin-Schreier symbol. Each
noncommutative summand has a rather simple description: it is the
crossed product of a commutative -algebra by a finite group.
The talk will be elementary, starting from the scratch with the
definition of .