On arbitrarily regular conforming virtual element methods for elliptic partial differential equations
The Virtual Element Method (VEM) is a very effective framework to design numerical approximations with high global regularity to the solutions of elliptic partial differential equations. In this paper, we review the construction of such approximations for an elliptic problem of order p_1 using conforming, finite dimensional subspaces of H^p_2(Ω), where p_1 and p_2 are two integer numbers such that p_2 ≥ p_1 ≥ 1 and Ω∈ R^2 is the computational domain. An abstract convergence result is presented in a suitably defined energy norm. The space formulation and major aspects such as the choice and unisolvence of the degrees of freedom are discussed, also providing specific examples corresponding to various practical cases of high global regularity. Finally, the construction of the "enhanced" formulation of the virtual element spaces is also discussed in details with a proof that the dimension of the "regular" and "enhanced" spaces is the same and that the virtual element functions in both spaces can be described by the same choice of the degrees of freedom.
READ FULL TEXT