A CASE FOR 14 DIMENSIONS

Extended superalgebras of types A, B, C, heterotic and type-I are all derived as solutions to a BPS equation in 14 dimensions with signature (11,3). The BPS equation as well as the solutions are covariant under SO(11,3). This shows how supersymmetries with N less than or equal to 8 in four dimensions have their origin in the same superalgebra in 14 D. The solutions provide different bases for the same superalgebra in 4D, and the transformations among bases correspond to various dualitie s. (C) 1997 Elsevier Science B.V.