(0,2)-NONCRITICAL STRINGS IN 6 DIMENSIONS

Type IIB strings compactified on K3 have a rich structure of solitonic strings, transforming under SO(21,5,Z). We derive the BPS tension for mula for these strings, and discuss their properties, in particular, t he points in the moduli space where certain strings become tensionless , By examining these tensionless string limits, we shed some further l ight on the conjectured dual M-theory description of this compactifica tion. (C) 1997 Elsevier Science B.V.