Abstract
Type-II strings in D = 5 contain particle-like 1/8
supersymmetric BPS states. In this note we give a string-network
representation of such states by considering (periodic) non-planar
(p,q,r)-string networks of eight dimensional type II string theory
on T3. We obtain the BPS mass formula of such states, in terms of
charges and generating-vectors of the torus, and show its invariance
under an SL(3,
) × SL(3,) group of
transformations. Results are then generalized to string-networks
associated with the SL(5,) U-duality in seven dimensions. We
also discuss reinterpretation of the above (D = 5) mass formula in
terms of BPS states in world-volume theories of U2-branes in D = 8.