Duality, entropy, and ADM mass in supergravity

We consider the Bekenstein-Hawking entropy-area formula in four dimensional extended ungauged supergravity and its electric-magnetic duality property. Symmetries of both large'' and small'' extremal black holes are considered, as well as the ADM mass formula for N = 4 and N = 8 supergravity, preserving different fraction of supersymmetry. The interplay between BPS conditions and duality properties is an important aspect of this investigation.