Anomaly matching and syzygies in N=1 gauge theories

We investigate the connection between the moduli space of N = 1 supersymmetric gauge theories and the set of polynomial gauge invariants constrained by classical/quantum relations called syzygies. We examine the existence of a superpotential reproducing these syzygies and the link with the 't Hooft anomaly matching between the fundamental fields at high energy and the gauge invariant degrees of freedom at low energy for the flavour symmetry group. We show that the anomaly matching is equivalent to the vanishing of the flavour anomaly on the normal space to the manifold defined by the syzygies. For normal spaces in a real representation of the flavour group we strengthen the connection between the 't Hooft anomaly matching and the existence of a superpotential by constructing a flavour invariant polynomial whose gradient vanishes at least on the solutions of the syzygies. This corroborates a recent definition of confining theories. We illustrate our general result by considering two examples based on the SU(N-c) and Spin(7) gauge theories. We also examine the role of syzygies in the context of non-Abelian duality. We emphasize the relevance of non-perturbative effects in the dual magnetic theories in proving the equivalence of the electric and magnetic syzygies. (C) 1999 Elsevier Science B.V. All rights reserved.