Minimization of Functional Majorant in a Posteriori Error Analysis Based on 𝐻(div) Multigrid-Preconditioned CG Method

Table 1

Friedrich's constant for the unit square domain computed from the generalized eigenvalue problem (3.7) on nested uniform meshes.

Level	Mesh size ℎ	Error	𝐶Ω
1	2^−1	0.04830238374264	0.17677669529663
2	2^−2	0.01595356174205	0.20912551729722
3	2^−3	0.00424589066153	0.22083318837774
4	2^−4	0.00107875817236	0.22400032086690
5	2^−5	0.00027079918172	0.22480827985755
6	2^−6	0.00006776967260	0.22501130936667
7	2^−7	0.00001694679400	0.22506213224527
8	2^−8	0.00000423697210	0.22507484206717
9	2^−9	0.00000105926003	0.22507801977924
Theory	0	0	0.22507907903928