Aspects of Space - Time Dualities

Duality groups of Abelian gauge theories on four manifolds and their reduction to two dimensions are considered. The duality groups include elements that relate different space-times in addition to relating different gauge-coupling matrices. We interpret (some of) such dualities as the geometrical symmetries of compactified theories in higher dimensions. In particular, we consider compactifications of a (self-dual) 2form in 6−D, and compactifications of a self-dual 4-form in 10−D. Relations with a self-dual superstring in 6−D and with the type IIB superstring are discussed. CERN-TH/96-127 May 1996 On leave of absence from the Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel; e-mail address: [email protected] e-mail address: [email protected]