a1 Department of Mathematics, The University College of Wales, Aberystwyth SY23 3BZ, Dyfed, Wales
Methods are developed for determining the decomposition matrices for the spin characters of the symmetric groups Sn for an odd prime p. Some general results are obtained which are non-trivial modifications of the corresponding results for ordinary characters. The methods are used to determine the decomposition matrices for 3 ≦ n ≦ ll, and p = 3 but with an interesting ambiguity in the case n = 9. The second author will deal separately with the cases p = 5, 7, 11.
(Received June 05 1987)
(Revised August 18 1987)