We study electric-magnetic duality in the chiral ring of a supersymmetric
U(N_c) gauge theory with adjoint and fundamental matter, in presence of a
general confining phase superpotential for the adjoint and the mesons. We find
the magnetic solution corresponding to both the pseudoconfining and higgs
electric vacua. By means of the Dijkgraaf-Vafa method, we match the effective
glueball superpotentials and show that in some cases duality works exactly
offshell. We give also a picture of the analytic structure of the resolvents in
the magnetic theory, as we smoothly interpolate between different higgs vacua
on the electric side.Comment: 54 pages, harvmac. v2: typos correcte