Fine error bounds for approximate asymmetric saddle point problems

Fuente: arXiv
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Main Author: Ruas, Vitoriano
Format: Preprint
Published: 2023
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_version_ 1866910348854951936
author Ruas, Vitoriano
author_facet Ruas, Vitoriano
contents The theory of mixed finite element methods for solving different types of elliptic partial differential equations in saddle point formulation is well established since many decades. This topic was mostly studied for variational formulations defined upon the same product spaces of both shape- and test-pairs of primal variable-multiplier. Whenever either these spaces or the two bilinear forms involving the multiplier are distinct, the saddle point problem is asymmetric. The three inf-sup conditions to be satisfied by the product spaces stipulated in work on the subject, in order to guarantee well-posedness, are well known. However, the material encountered in the literature addressing the approximation of this class of problems left room for improvement and clarifications. After making a brief review of the existing contributions to the topic that justifies such an assertion, in this paper we set up finer global error bounds for the pair primal variable-multiplier solving an asymmetric saddle point problem. Besides well-posedness, the three constants in the aforementioned inf-sup conditions are identified as all that is needed for determining the stability constant appearing therein, whose expression is exhibited. As a complement, refined error bounds depending only on these three constants are given for both unknowns separately.
format Preprint
id arxiv_https___arxiv_org_abs_2307_03742
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Fine error bounds for approximate asymmetric saddle point problems
Ruas, Vitoriano
Numerical Analysis
65N30, 70G75, 74A15, 76M30, 78M30, 80M30
The theory of mixed finite element methods for solving different types of elliptic partial differential equations in saddle point formulation is well established since many decades. This topic was mostly studied for variational formulations defined upon the same product spaces of both shape- and test-pairs of primal variable-multiplier. Whenever either these spaces or the two bilinear forms involving the multiplier are distinct, the saddle point problem is asymmetric. The three inf-sup conditions to be satisfied by the product spaces stipulated in work on the subject, in order to guarantee well-posedness, are well known. However, the material encountered in the literature addressing the approximation of this class of problems left room for improvement and clarifications. After making a brief review of the existing contributions to the topic that justifies such an assertion, in this paper we set up finer global error bounds for the pair primal variable-multiplier solving an asymmetric saddle point problem. Besides well-posedness, the three constants in the aforementioned inf-sup conditions are identified as all that is needed for determining the stability constant appearing therein, whose expression is exhibited. As a complement, refined error bounds depending only on these three constants are given for both unknowns separately.
title Fine error bounds for approximate asymmetric saddle point problems
topic Numerical Analysis
65N30, 70G75, 74A15, 76M30, 78M30, 80M30
url https://arxiv.org/abs/2307.03742