The Gervais-Neveu-Felder equation for the Jordanian quasi-Hopf U-h;y(sl(2)) algebra

Using a contraction procedure, we construct a twist operator that satisfies a shifted cocycle condition, and leads to the Jordanian quasi-Hopf U-h;y(s l(2)) algebra. The corresponding niversal R-h(y) matrix obeys a Gervais-Nev eu-Felder equation associated with the U-h;y(sl(2)) algebra. For a class of representations, the dynamical Yang-Baxter equation may be expressed as a compatibility condition for the algebra of the Lax operators.