A Polynomial Invariant for Flat Virtual Links
  This paper gives a polynomial invariant for flat virtual links. In the case of one component, the polynomial specializes to Turaev's virtual string polynomial. We show that Turaev's polynomial has the property that it is non-zero precisely when there is no filamentation of the knot, as described by Hrencecin and Kauffman. Schellhorn has provided a version of filamentations for flat virtual links. Our polynomial has the property that if there is a filamentation, then the polynomial is 0. The converse fails, although if the polynomial is 0, then it turns out to be easy to determine if there is a filamentation. 
Louis H. Kauffman and R. Bruce Richter