On Integrable c < 1 Open – Closed String Theory

The integrable structure of open–closed string theories in the (p, q) conformal minimal model backgrounds is presented. The relation between the τ–function of the closed string theory and that of the open–closed string theory is uncovered. The resulting description of the open–closed string theory is shown to fit very naturally into the framework of the sl(q,C) KdV hierarchies. In particular, the twisted bosons which underlie and organise the structure of the closed string theory play a similar role here and may be employed to derive loop equations and correlation function recursion relations for the open–closed strings in a simple way. ∗ Lindemann Fellow † e-mail: [email protected]