Loop representation for 2-D Wilson lattice fermions in a scalar   background field
  We show that the fermion determinant for 2-D Wilson lattice fermions coupled to an external scalar field is equivalent to self avoiding loops interacting with the external field. In an application of the resulting formula we integrate the scalar field with a Gaussian action to generate the N-component Gross-Neveu model. The loop representation for this model is discussed. 
Christof Gattringer (MIT)