A Sobolev inequality with reciprocal weights

We give a Sobolev inequality with the weight K(x)K(x) belonging to the class A2∩GnA2∩Gn for the function |u|t|u|t and the weight K(x)−1K(x)−1 for |∇u|2|∇u|2. The constant in the relevant inequality is seen to depend on the GnGn and A2A2 constants of the weight.