  Using deformation theory based on BRST cohomology, a supergravity model is
constructed which interpolates through a continuous deformation parameter
between new minimal supergravity with an extra U(1) gauge multiplet and
standard supergravity with local R-symmetry in a formulation with a nonstandard
set of auxiliary fields. The deformation implements an electromagnetic duality
relating the extra U(1) to the R-symmetry. A consistent representative of the
R-anomaly in the model is proposed too.
