The Geometry of Fractional D1-branes
  We find explicit solutions of Type IIB string theory on R^4/Z_2 corresponding to the classical geometry of fractional D1-branes. From the supergravity solution obtained, we capture perturbative information about the running of the coupling constant and the metric on the moduli space of N=4, D=2 Super Yang Mills. 
Daniel Bundzik and Anna Tollst\'en