We prove a general formula for computing the Schur index of A tensor F(X),
where A is a central simple algebra over a field F and F(X) is the function
field of a twisted flag variety X; that is, X is a projective variety over F
such that there is an algebraic group action on X by some adjoint semisimple
group G, where the action becomes transitive on passage to the separable
closure of F. The formula depends on the calculation of K_0(X;A) made by the
second author. When G is a classical simple group of inner type, the
corresponding varieties X are classified, and explicit concise index
reduction formulas are given for each X.
This paper has appeared in the journal K-theory, 10 (1996), 517-596, and
hence the dvi file has been removed.