(1) Mathematical Institute, 24-29 St. Giles, OX1 3LB Oxford, England
Abstract:
Let be the Hecke algebra of the symmetric group over a field K of characteristic and a primitive -th root of one in K. We show that an -module is projective if and only if its restrictions to any-parabolic subalgebra of is projective.Moreover, we give a new construction of blocks of -parabolic subalgebras, in terms of skew group algebras over local commutativealgebras. Received: 30 June 2003
be the Hecke algebra of the symmetric group 
over a field K of characteristic 
and 
a primitive 
-th root of one in K. We show that an 
-module is projective if and only if its restrictions to any
-parabolic subalgebra of 
is projective.Moreover, we give a new construction of blocks of 
-parabolic subalgebras, in terms of skew group algebras over local commutativealgebras. Received: 30 June 2003