Abstract:
The main goal of this paper is to prove the denseness of $C_0^\infty(\Omega)$ in $L_{p(x)}(\Omega)$ for $0<p(x)<1$. We construct a family of potential type identity approximations and prove a modular inequality in $L_{p(x)}(\Omega)$ for $0<p(x)<1$. As an application we prove an analogue of the Kolmogorov–Riesz type compactness theorem in $L_{p(x)}(\Omega)$ for $0<p(x)<1$.
Key words and phrases:$L_{p(x)}$ spaces, denseness, potential type identity approximations, modular inequality, compactness.