F^4 Terms in N=4 String Vacua
arXiv:hep-th/9611205 · doi:10.1016/S0920-5632(97)00079-0
Abstract
We discuss $F_{μν}^4$ terms in torroidal compactifications of type-I and heterotic SO(32) string theory. We give a simple argument why only short BPS multiplets contribute to these terms at one loop, and verify heterotic-type-I duality to this order.
10 pages, Latex. A statement about superinvariants was corrected. Minor cosmetic changes were also made. To appear in Proceedings of Trieste Spring School and Workshop, April 1996