An index theory for projective families of elliptic pseudodifferential
operators is developed. The topological and the analytic index of such
a family both take values in twisted K–theory of the parametrizing
space, X. The main result is the equality of these two notions of index
when the twisting class is in the torsion subgroup of H3(X;Z).
The Chern character of the index class is then computed.
Keywords
projective vector bundles, twisted
K–theory, projective families of elliptic operators,
Index theorem, determinant lines, twisted Chern character