IR dynamics on branes and space-time geometry

the type I theory compactified on T3. When the D5-brane wraps the T3 it yields a D2-brane in seven dimensions. In the leading approximation the moduli space of vacua of the three dimensional field theory on the brane is T4Z2. The dual M theory description of this theory is a compactification on K3 and our 2-brane is the eleven dimensional 2-brane at a point in K3. We use this fact to conclude that strong coupling IR effects in the three dimensional theory on the brane turn its moduli space into a K3. This interpretation allows us to solve various strongly coupled gauge theories in three dimensions by identifying their Coulomb branch with a piece of a (sometime singular) K3.