Higher Forms and Membranes in 4D Supergravities

We review the dynamical generation of coupling constants in 4D supergravity by means of gauge three-form fields. The latter are introduced as components of particular chiral supermultiplets and can be coupled to membranes preserving local supersymmetry. Such a set-up naturally arises from type-II string compactifications on Calabi-Yau manifolds with fluxes. We present generic 4D $\mathcal N=1$ supergravity models with three-form multiplets and study domain wall solutions supported by membranes, which interpolate between vacua with different values of the cosmological constant.