+ -J ISING-MODEL IN 2D AND OF GENERAL COMPOSITION/

We study the effects of frustration in terms of eigenstates within the Pfaffian (or Grassman variable) formalism for the Ising system. The d estruction of ferromagnetic order is due to the introduction, at a cri tical defect concentration, of eigenstates extended over the entire sy stem. This effect is characterized by an exponent p which describes ho w the number of extended states scales with the size of the system. Th is exponent is found to take a constant value in the ground-state spin -glass phase and changes abruptly at the transition point.