John domains Radial functions Reverse doubling weights Weighted Poincaré inequality Weighted Sobolev inequality Embedding theorems Power weights Sobolev spaces Caffarelli-Kohn-Nirenberg inequalities Convolution Cusp domains Elliptic system Fractional Sobolev spaces Fractional integrals Fractional integration Fractional norms Fractional-order Sobolev spaces Harmonic oscillator Hermite expansions Irregular domains Laguerre expansions Muckenhoupt weights Multipliers Poincaré inequality Potential spaces Real interpolation Riesz potentials S-John domains Sobolev inequality Trace inequalities