Some observations on Babu\vs}ka and Brezzi theories
- Cite this article as:
- Xu, J. & Zikatanov, L. Numer. Math. (2003) 94: 195. doi:10.1007/s002110100308
Summary. Some observations are made on abstract error estimates for Galerkin approximations based on Babuška-Brezzi conditions. A basic error estimate due to Babuška is sharpened by means of an identity that \(\| P\|=\|I-P \|\) for any nontrivial idempotent operator P. Some remarks are also made on the Brezzi's theory for mixed variational problems and their Galerkin approximations.