Abstract
We construct a new Fortin operator for the lowest order Taylor–Hood element, which is uniformly stable both in \(L^2\) and \(H^1\). The construction, which is restricted to two space dimensions, is based on a tight connection between a subspace of the Taylor–Hood velocity space and the lowest order Nedelec edge element. General shape regular triangulations are allowed for the \(H^1\)-stability, while some mesh restrictions are imposed to obtain the \(L^2\)-stability. As a consequence of this construction, a uniform inf–sup condition associated the corresponding discretizations of a parameter dependent Stokes problem is obtained, and we are able to verify uniform bounds for a family of preconditioners for such problems, without relying on any extra regularity ensured by convexity of the domain.

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References
Arnold, D.N., Brezzi, F., Fortin, M.: A stable finite element method for Stokes equations. Calcolo 21, 337–344 (1984)
Bramble, J.H., Pasciak, J.E.: Iterative techniques for time dependent Stokes problems. Comput. Math. Appl. 33(1–2), 13–30 (1997) (approximation theory and applications)
Bramble, J.H., Pasciak, J.E., Steinbach, O.: On the stability of the \(L^2\) projection in \(H^1(\Omega )\). Math. Comp. 71, 147–156 (2001)
Brezzi, F.: On the existence, uniqueness and approximation of saddle-point problems arising from L0 multipliers. RAIRO Anal. Numér. 8, 129–151 (1974)
Brezzi, F., Fortin, M.: Mixed and Hybrid Finite Element Methods. Springer, Berlin (1991)
Cahouet, J., Chabard, J.-P.: Some fast 3D finite element solvers for the generalized Stokes problem. Internat. J. Numer. Methods Fluids 8(8), 869–895 (1988)
Clement, P.: Approximation by finite element functions using local regularization. RAIRO Anal. Numér. 9, 77–84 (1975)
Costabel, M., McIntosh, A.: On Bogovskiĭ and regularized Poincaré integral operators for de Rham complexes on Lipschitz domains. http://arxiv.org/abs/0808.2614v1
Falk, R.S.: A Fortin operator for two-dimensional Taylor–Hood elements. Math. Model. Numer. Anal. 42, 411–424 (2008)
Galdi, G.P.: An introduction to the mathematical theory of the Navier–Stokes equations, vol 1. In: Linearized Steady problems. Springer Tracts in Natural Philosophy, vol. 38. Springer, New York (1994)
Geissert, M., Heck, H., Hieber, M.: On the equation \(\text{ div} u = g\) and Bogovskiĭ’s operator in Sobolev spaces of negative order. Oper. Theory Adv. Appl. 168, 113–121 (2006)
Girault, V., Raviart, P.-A.: Finite element methods for Navier–Stokes equations: theory and algorithms. Springer Series in Computational Mathematics, vol. 5. Springer, Berlin (1986)
Kolev, T., Vassilevski, P.: Regular Decomposition of H(div) Spaces. Comput. Methods Appl. Math. (to appear)
Lay, M.-J., Schumaker, L.L.: Spline functions on triangulations. In: Encyclopedia of Mathematics and its Applications. Cambridge University Press, London (2007).
Mardal, K.-A., Schöberl, J., Winther, R.: A uniform inf-sup condition with applications to preconditioning. arXiv:1201.1513v1,2012.
Mardal, K.-A., Winther, R.: Preconditioning discretizations of systems of partial differential equations. Numer. Linear Algebra Appl. 18, 1–40 (2011)
Mardal, K.-A., Winther, R.: Uniform preconditioners for the time dependent Stokes problem. Numer. Math. 98(2), 305–327 (2004)
Mardal, K.-A., Winther, R.: Erratum: “Uniform preconditioners for the time dependent Stokes problem” [Numer. Math. 98(2), 2004, pp. 305–327]. Numer. Math. 103(1), 171–172 (2006)
Olshanskii, M.A., Peters, J., Reusken, A.: Uniform preconditioners for a parameter dependent saddle point problem with application to generalized Stokes interface equations. Numer. Math. 105, 159–191 (2006)
Turek, S.: Efficient Solvers for Incompressible Flow Problems. Springer, Berlin (1999)
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K.-A. Mardal was supported by the Research Council of Norway through Grant 209951 and a Centre of Excellence grant to the Centre for Biomedical Computing at Simula Research Laboratory. R. Winther was supported by the Research Council of Norway through a Centre of Excellence grant to the Centre of Mathematics for Applications.
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Mardal, KA., Schöberl, J. & Winther, R. A uniformly stable Fortin operator for the Taylor–Hood element. Numer. Math. 123, 537–551 (2013). https://doi.org/10.1007/s00211-012-0492-6
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DOI: https://doi.org/10.1007/s00211-012-0492-6