THE GROUP E_6 AND THE FORMULATION OF STRING THEORY

摘要

The group E_6 arises from the breaking of the E_8xE_8 symmetry of the heteròtic string theory. It has, a natural interpretation in terms of octonions and the formulation of string theory in terms of elements of this division algebras is noted. It is proven that a spinor bilinear can be formed which is invariant under E_8 and that the factorization of open superstring amplitudes may be extended to the exceptional group.