IIA ten-forms and the gauge algebras of maximal supergravity theories

Abstract

We show that IIA supergravity can be extended with two independent 10-form potentials. These give rise to a single BPS IIA 9-brane. We investigate the bosonic gauge algebra of both IIA and IIB supergravity in the presence of 10-form potentials and point out an intriguing relation with the symmetry algebra E11, which has been conjectured to be the underlying symmetry of string theory/M-theory.