**
Eric Bergshoeff
**

**Dual Doubled Geometry
**

**Abstract
**

It is well-known that a T-duality covariant formulation of the fundamental branes of toroidally compactified string theory with 32 supercharges requires a doubled geometry. We will probe this doubled geometry with dual fundamental branes, i.e. solitonic branes. Restricting ourselves first to solitonic branes with more than two transverse directions we find that the doubled geometry corresponds to an effective wrapping rule for the solitonic branes which is dual to the wrapping rule for fundamental branes. This dual wrapping rule can be understood by the presence of Kaluza-Klein monopoles. Extending our analysis to solitonic branes with less than or equal to two transverse directions we find that the solitonic wrapping rule suggests the existence of a class of generalized Kaluza-Klein monopoles in ten dimensions.