Improved error estimates for Hybrid High-Order discretizations of Leray-Lions problems

Abstract: We derive novel error estimates for Hybrid High-Order (HHO) discretizations of Leray-Lions problems set in W^1,p with p in (1,2]. Specifically, we prove that, depending on the degeneracy of the problem, the convergence rate may vary between (k+1)(p-1) and (k+1), with k denoting the degree of the HHO approximation. These regime-dependent error estimates are illustrated by a complete panel of numerical experiments.