Title: Mixed finite element methods for elliptic problems Authors: Douglas N. Arnold Source: Comput. Methods Appl. Mech. Engrg. 82 (1990), pp. 281-300 Status: Published Abstract: This paper treats the basic ideas of mixed finite element methods at an introductory level. Although the viewpoint presented is that of a mathematician, the paper is aimed at practitioners and the mathematical prerequisites are kept to a minimum. A classification of variational principles and of the corresponding weak formulations and Galerkin methods--displacement, equilibrium, and mixed--is given and illustrated through four significant examples. The advantages and disadvantages of mixed methods are discussed. The concepts of convergence, approximability, and stability and their interrelations are developed, and a resume is given of the stability theory which governs the performance of mixed methods. The paper concludes with a survey of techniques that have been developed for the construction of stable mixed methods and numerous examples of such methods. Keywords: mixed method, finite element, variational principle Subj. class.: 65N30, 73C35, 73K25 URL: http://ima.umn.edu/~arnold/papers/mixed.pdf