A bound on 6D N=1 supergravities

We prove that there are only finitely many distinct semi-simple gauge groups and matter representations possible in consistent 6D chiral (1, 0) supergravity theories with one tensor multiplet. The proof relies only on features of the low-energy theory; the consistency conditions we impose are that anomalies should be cancelled by the Green-Schwarz mechanism, and that the kinetic terms for all fields should be positive in some region of moduli space. This result does not apply to the case of the non-chiral (1, 1) supergravities, which are not constrained by anomaly cancellation.