Abstract: Instead of using the full polynomial space, harmonic finite element methods are designed where
only harmonic polynomials are employed in the computation. A nonconforming quadratic harmonic finite
element is defined on general triangular grids. A family of Pk conforming harmonic finite elements of any
degree k is constructed on HTC macro triangular grids, where a base triangle is split in to three by connecting
its barycenter to its three vertices. The optimal order of convergence is proved, and confirmed by
numerical examples.