DUAL PAIRS OF TYPE-II STRING COMPACTIFICATION

Using a U-duality symmetry of type II compactification on T-4 represented by triality action on the T-duality group, and applying the adiabatic argument we construct dual pairs of type II compactifications in lower dimensions. The simplicity of this construction makes it an ideal set up for testing various conjectures about string dualities. In some of these models the type II string has a perturbative non-abelian gauge symmetry. Examples include models with N = 2, 4, 6 supersymmetry in four dimensions. There are also self-dual (in the sense of S - T exchange symmetric) N = 2 and N = 6 examples. A generalization of the adiabatic argument can be used to construct dual pairs of models with N = 1 supersymmetry.