IIA/B, wound and wrapped

We examine the T-duality relation between 1+1 NCOS and the DLCQ limit of typeIIA string theory. We show that, as long as there is a compact dimension, onecan meaningfully define an `NCOS' limit of IIB/A string theory even in theabsence of D-branes (and even if there is no B-field). This yields a theory ofclosed strings with strictly positive winding, which is T-dual to DLCQ IIA/Bwithout any D-branes. We call this the Type IIB/A Wound String Theory. Theexistence of decoupled sectors can be seen directly from the energy spectrum,and mirrors that of the DLCQ theory. It becomes clear then that all of thedifferent p+1 NCOS theories are simply different states of this single WoundIIA/B theory which contain D-branes. We study some of the properties of thistheory. In particular, we show that upon toroidal compactification, Woundstring theory is U-dual to various Wrapped Brane theories which contain OMtheory and the ODp theories as special states.Comment: LaTeX 2e, 36+1 pages, 1 ps figur