  This paper is devoted to the study of fractional (q,p)-Sobolev-Poincare
inequalities in irregular domains. In particular, we establish (essentially)
sharp fractional (q,p)-Sobolev-Poincare inequality in s-John domains and in
domains satisfying the quasihyperbolic boundary conditions. When the order of
the fractional derivative tends to 1, our results tends to the results for the
usual derivative. Furthermore, we verified that those domains that support the
fractional (q,p)-Sobolev-Poincare inequality together with a separation
property are s-diam John domains for certain s, depending only on the
associated data. We also point out an inaccurate statement in [2].
