DUALITY RELATIONS FOR POTTS CORRELATION-FUNCTIONS - COMMENT

In a recent paper by Wu [Phys. Lett. A 228 (1997) 43] the three-point correlation of the q-state Potts model on a planar graph was related t o ratios of dual partition functions under fixed boundary conditions. It was claimed that the method employed could straightforwardly be app lied to higher correlations as well; this is however not true. By expl icitly considering the four-point correlation we demonstrate how the a ppearance of non-well-nested connectivities invalidates the method. (C ) 1997 Published by Elsevier Science B.V.