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arXiv · 2607.02362

Sobolev stability of the $L^2$-projection on hybrid meshes

Lars Diening·Viktoria Lingert·Tabea Tscherpel
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Abstract

We establish $L^p$- and $W^{1,p}$-stability of the $L^2$-projection onto mapped Lagrange finite elements on hybrid meshes consisting of triangles and convex quadrilaterals arising from adaptive mesh refinement. If $K$ is the (tensor product) degree of polynomials of the discretisation, then we show, in particular, $W^{1,2}$-stability for all $K\geq 2$ for the Q-RG and Q-RB refinements. This extends results by Ali, Funken, and Schmidt (2022) which hold for the range $2 \leq K \leq 9$ for initial meshes consisting of parallelograms. Our proof relies on an extension of the technique by Diening, Storn and Tscherpel (2021) to general convex quadrilaterals.

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Lars Diening, Viktoria Lingert, Tabea Tscherpel. 2026-07-02. Sobolev stability of the $L^2$-projection on hybrid meshes. https://arxiv.org/abs/2607.02362

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