New ``Gauge'' Theories In Six Dimensions

More general constructions are given of six-dimensional theories that look at low energy like six-dimensional super Yang-Mills theory. The constructions start with either parallel fivebranes in Type IIB, or M-theory on $(\C^2\times\S^1)/\Gamma$ for $\Gamma$ a suitable finite group. Via these constructions, one can obtain six-dimensional theories with any simple gauge group, and $SU(r)$ theories with any rational theta angle. A matrix construction of these theories is also possible.