NONLINEAR EXTENSIONS OF THE REPARAMETRIZATION ALGEBRA: ALGEBRAIC CONSTRUCTION, INVARIANTS AND ANOMALIES

摘要

We perform a class of nonlinear extensions of the reparametrization algebra at arbitrary dimensions. Our extended algebras reproduce in the one-dimensional limit the well-known -ones. We point out the existence of a family of reparametrization invariant functions for which this property is untouched by the extension procedure. This allows to calculate the improvement of the gravitational anomaly within the extended symmetry.