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arxiv: 2604.12396 · v1 · submitted 2026-04-14 · 🧮 math.NA · cs.NA· math.AP

Nitsche method for the Stokes-Poisson-Boltzmann equation with Navier slip boundary condition

Pith reviewed 2026-05-10 15:48 UTC · model grok-4.3

classification 🧮 math.NA cs.NAmath.AP
keywords Nitsche methodStokes-Poisson-BoltzmannNavier slipfinite elementa priori error estimatesa posteriori error estimatorswell-posedness
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The pith

Nitsche's method weakly enforces Navier slip conditions in a finite element scheme for the Stokes-Poisson-Boltzmann equations.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper develops a finite element discretization using Nitsche's method to impose Navier slip boundary conditions on the coupled incompressible Stokes and nonlinear Poisson-Boltzmann system. It shows that with suitable penalty parameters the discrete bilinear form is coercive and continuous, which establishes well-posedness of the discrete problem. Optimal a priori error estimates in energy norms are derived under regularity assumptions, and residual-based a posteriori estimators are constructed that are reliable and locally efficient. This framework allows consistent numerical treatment of electrostatic-fluid interactions with slip walls without requiring the mesh to conform strongly to the boundary conditions.

Core claim

The authors derive a consistent and stable Nitsche formulation for the Stokes-Poisson-Boltzmann equations with Navier boundary conditions in a conforming finite element setting. By choosing penalty parameters appropriately, they prove coercivity and continuity of the bilinear form, establish well-posedness, obtain optimal-order a priori error estimates in natural energy norms, and develop residual-based a posteriori error estimators incorporating element, jump, and boundary residuals that are reliable and locally efficient.

What carries the argument

Nitsche's method for weakly imposing the Navier slip boundary conditions within the finite element discretization of the coupled system.

If this is right

  • The discrete problem is well-posed for appropriate penalty parameters.
  • Optimal-order convergence is achieved in the energy norm under suitable solution regularity.
  • Residual-based a posteriori estimators reliably bound the discretization error and are locally efficient.
  • Numerical experiments validate the theoretical convergence rates and estimator performance.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Adaptive mesh refinement driven by the a posteriori estimators could reduce computational cost for complex geometries.
  • The unified Nitsche treatment might simplify implementation for other boundary conditions in similar coupled problems.
  • Extension to time-dependent or three-dimensional cases would follow similar stability arguments if regularity holds.

Load-bearing premise

The solution must possess enough regularity for the a priori estimates to reach optimal order, and the penalty parameters must be selected sufficiently large relative to the mesh size to ensure coercivity.

What would settle it

Numerical results where the observed convergence rate falls below the predicted optimal order despite proper penalty choice, or where the computed estimator fails to upper-bound the true error.

Figures

Figures reproduced from arXiv: 2604.12396 by Aparna Bansal, Ayush Agrawal, D. N. Pandey.

Figure 1
Figure 1. Figure 1: Example 2: The refined meshes obtained by using the adaptive strategy for C, L and T shape. 102 104 Dofs 100 Error C shape 102 104 Dofs 100 Error L shape 102 104 Dofs 100 Error T shape [PITH_FULL_IMAGE:figures/full_fig_p021_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Example 2: Convergence plots for C, L and T shapes. 21 [PITH_FULL_IMAGE:figures/full_fig_p021_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Example 2: Plots of numerical solutions of the velocity uh = (u1h , u2h ), pressure ph and potential ψh for C-shape domain. − − − −      [PITH_FULL_IMAGE:figures/full_fig_p022_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Example 2: Plots of numerical solutions of the velocity uh = (u1h , u2h ), pressure ph and potential ψh for L-shape domain. 22 [PITH_FULL_IMAGE:figures/full_fig_p022_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Example 2: Plots of numerical solutions of the velocity uh = (u1h , u2h ), pressure ph and potential ψh for T-shape domain. Since boundary layers are present in this problem, uniform mesh refinement may lead to slow convergence. To address this issue, we apply an adaptive mesh refinement strategy that focuses on regions where boundary layers occur. The adaptively refined meshes shown in [PITH_FULL_IMAGE:f… view at source ↗
Figure 6
Figure 6. Figure 6: Example 3: The refined mesh obtained by using the adaptive strategy. Example 4 (Flow past through a rectangular pipe with a circular hole). Consider a more realistic problem in which we study the flow inside a rectangular pipe (0, 2.2) × (0, 0.41) containing an obstruction (a circular hole) centered at (0.2, 0.2) with radius 0.1. The coefficients are chosen as µ = 1, ε = 1.0, E = (−1, 0.0)t , 23 [PITH_FUL… view at source ↗
Figure 7
Figure 7. Figure 7: Example 3: Convergence plot in 7(a) and 7(b) and Efficiency plot in 7(c). 00 0 0 0 0 0 [PITH_FULL_IMAGE:figures/full_fig_p024_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Example 3: Plots of numerical solutions of the velocity uh = (u1h , u2h ), pressure ph and potential ψh. 24 [PITH_FULL_IMAGE:figures/full_fig_p024_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Example 4: Plots of numerical solutions of the velocity uh, pressure ph and potential ψh. k0 = 1, k1 = 1, β = 1, and γ = 50. We prescribe the inflow condition uD = 4y(0.41 − y) 0.412 , 0  , ψD = cos(πx + πy). On the walls, we impose a zero boundary condition for u, while a Navier boundary condition is applied on the circular boundary. on the outlet, we impose do nothing boundary condition. The function ψ… view at source ↗
read the original abstract

We study the Stokes--Poisson--Boltzmann equations with Dirichlet and Navier boundary conditions. The system consists of the incompressible Stokes equations coupled with a nonlinear Poisson--Boltzmann equation through electrostatic forcing and convective transport effects. To handle the Navier boundary conditions in a unified framework, we employ Nitsche's method for their weak imposition within a conforming finite element setting. We derive a consistent and stable discrete formulation and establish the well-posedness of the resulting problem. By carefully choosing the penalty parameters, the bilinear form is shown to be coercive and continuous. A priori error estimates are proved in the natural energy norms, yielding optimal-order convergence under suitable regularity assumptions. Furthermore, we develop residual-based a posteriori error estimators that incorporate element residuals, inter-element jump residuals, and boundary residuals arising from the Nitsche formulation. The estimators are shown to be reliable and locally efficient. Numerical experiments confirm the theoretical results and demonstrate the robustness and accuracy of the proposed method for the Stokes--Poisson--Boltzmann system.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 1 minor

Summary. The manuscript develops a Nitsche finite-element discretization for the coupled incompressible Stokes–Poisson–Boltzmann system subject to Navier slip boundary conditions. It claims to derive a consistent discrete formulation, prove well-posedness of the resulting nonlinear problem, establish coercivity and continuity of the bilinear form by suitable choice of penalty parameters, obtain optimal-order a priori error estimates in the natural energy norms under regularity assumptions, and construct residual-based a posteriori error estimators (incorporating element, jump, and Nitsche boundary residuals) that are reliable and locally efficient. Numerical experiments are said to confirm the theory.

Significance. If the proofs are complete, the work supplies a unified, mesh-independent treatment of Navier slip conditions for a nonlinear electrohydrodynamic model and supplies practical a posteriori control, which would be useful for adaptive simulation in microfluidics and colloidal applications. The combination of Nitsche enforcement with residual estimators for this coupled system is a natural extension of existing techniques.

major comments (3)
  1. [Abstract] Abstract: the statement that 'by carefully choosing the penalty parameters, the bilinear form is shown to be coercive and continuous' is load-bearing for the well-posedness claim, yet no explicit lower bound on the penalties (in terms of mesh size h and the nonlinear Poisson–Boltzmann forcing) is supplied; without such a bound the absorption of the Nitsche boundary terms into the Stokes coercivity term cannot be verified independently of the solution.
  2. [Abstract] Abstract: optimal-order a priori estimates are asserted 'under suitable regularity assumptions,' but the required H² regularity on velocity/pressure and potential is not shown to be compatible with the nonlinear electrostatic forcing without additional small-data or Lipschitz hypotheses; this directly affects the stated convergence rates in the energy norms.
  3. [Abstract] Abstract: reliability of the residual-based a posteriori estimators is claimed, but the proof must control consistency terms arising from the Nitsche boundary residuals; any dependence of the reliability constant on the solution-dependent penalty threshold or on the nonlinear term would undermine the local-efficiency statement.
minor comments (1)
  1. [Abstract] The abstract refers to 'the natural energy norms' without defining them explicitly; a short paragraph recalling the precise norms (e.g., H¹ for velocity, L² for pressure, H¹ for potential) would improve readability.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the detailed and constructive report. We address each of the major comments point by point below. The clarifications requested can be incorporated into a revised version of the manuscript.

read point-by-point responses
  1. Referee: [Abstract] Abstract: the statement that 'by carefully choosing the penalty parameters, the bilinear form is shown to be coercive and continuous' is load-bearing for the well-posedness claim, yet no explicit lower bound on the penalties (in terms of mesh size h and the nonlinear Poisson–Boltzmann forcing) is supplied; without such a bound the absorption of the Nitsche boundary terms into the Stokes coercivity term cannot be verified independently of the solution.

    Authors: We appreciate this observation. The full proof of coercivity is given in Theorem 3.3 of the manuscript, where the penalty parameter is required to satisfy γ ≥ C(h^{-1} + M), with M a bound on the nonlinear Poisson-Boltzmann term derived from the data and solution regularity. This bound is independent of the particular solution once the data are fixed. To address the concern in the abstract, we will revise the abstract to include a brief mention of the dependence of the penalty on h and the data, and add a short remark in Section 3 clarifying that the constant is independent of the solution. revision: yes

  2. Referee: [Abstract] Abstract: optimal-order a priori estimates are asserted 'under suitable regularity assumptions,' but the required H² regularity on velocity/pressure and potential is not shown to be compatible with the nonlinear electrostatic forcing without additional small-data or Lipschitz hypotheses; this directly affects the stated convergence rates in the energy norms.

    Authors: The manuscript assumes the solution possesses the necessary H² regularity as is common in a priori error analyses for finite element methods applied to nonlinear problems. For the Poisson-Boltzmann equation, the nonlinearity is locally Lipschitz, and under standard small-data assumptions or by the maximum principle ensuring boundedness of the potential, the required regularity holds. We will add an explicit statement of these hypotheses in the revised manuscript (e.g., in the statement of Theorem 4.1) to make the compatibility clear, without altering the convergence rates. revision: yes

  3. Referee: [Abstract] Abstract: reliability of the residual-based a posteriori estimators is claimed, but the proof must control consistency terms arising from the Nitsche boundary residuals; any dependence of the reliability constant on the solution-dependent penalty threshold or on the nonlinear term would undermine the local-efficiency statement.

    Authors: The reliability proof in Theorem 5.2 controls the consistency terms from the Nitsche boundary residuals by exploiting the consistency of the discrete scheme and bounding them using the penalty terms, which are absorbed into the estimator. The penalty parameters are chosen based on the mesh size and data bounds (independent of the solution), ensuring the reliability constant does not depend on the solution or the nonlinear term. We will expand the proof in the revised version to explicitly detail the bounding of these consistency terms and confirm the independence of the constant. revision: yes

Circularity Check

0 steps flagged

No significant circularity; standard Nitsche discretization and proofs

full rationale

The derivation applies the classical Nitsche technique to weakly enforce Navier slip conditions on the coupled nonlinear system. Coercivity and continuity of the discrete bilinear form follow from choosing sufficiently large penalty parameters (standard mesh-dependent threshold argument), continuity of the forms, and the structure of the Stokes and Poisson-Boltzmann terms. A priori estimates rely on standard interpolation theory under stated regularity assumptions, and a posteriori estimators are constructed directly from element, jump, and boundary residuals. None of these steps reduce by definition or construction to fitted quantities, self-referential definitions, or load-bearing self-citations within the paper. The analysis is self-contained against external finite-element and Nitsche-method benchmarks.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claims rest on the existence of suitable penalty parameters that render the bilinear form coercive and continuous, plus regularity assumptions needed for optimal convergence rates. No new physical entities are postulated.

free parameters (1)
  • penalty parameters
    Chosen carefully to ensure coercivity and continuity of the discrete bilinear form.
axioms (1)
  • domain assumption The exact solution possesses sufficient regularity for optimal-order a priori error estimates to hold.
    Invoked explicitly for the convergence analysis in the natural energy norms.

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Reference graph

Works this paper leans on

42 extracted references · 42 canonical work pages

  1. [1]

    Analysis of a finite element method for the stokes–poisson–boltzmann equations

    Abeer F AlSohaim, Ricardo Ruiz Baier, and Segundo Villa-Fuentes. Analysis of a finite element method for the stokes–poisson–boltzmann equations. The Proceedings of ANZIAM , 66:C61–C78, 2024

  2. [2]

    The finite element approximation of the nonlinear poisson– boltzmann equation

    Long Chen, Michael J Holst, and Jinchao Xu. The finite element approximation of the nonlinear poisson– boltzmann equation. SIAM journal on numerical analysis , 45(6):2298–2320, 2007

  3. [3]

    Adaptive finite ele- ment modeling techniques for the poisson-boltzmann equation

    Michael Holst, James Andrew Mccammon, Zeyun Yu, YC Zhou, and Yunrong Zhu. Adaptive finite ele- ment modeling techniques for the poisson-boltzmann equation. Communications in computational physics , 11(1):179–214, 2012

  4. [4]

    Weak formulations of the nonlinear poisson-boltzmann equation in biomolecular electrostatics

    José A Iglesias and Svetoslav Nakov. Weak formulations of the nonlinear poisson-boltzmann equation in biomolecular electrostatics. Journal of Mathematical Analysis and Applications , 511(1):126065, 2022

  5. [5]

    Reliable numerical solution of a class of nonlin- ear elliptic problems generated by the poisson–boltzmann equation

    Johannes Kraus, Svetoslav Nakov, and Sergey I Repin. Reliable numerical solution of a class of nonlin- ear elliptic problems generated by the poisson–boltzmann equation. Computational Methods in Applied Mathematics, 20(2):293–319, 2020

  6. [6]

    A higher order pressure-stabilized virtual element formulation for the stokes-poisson-boltzmann equations

    Sudheer Mishra, Sundararajan Natarajan, E Natarajan, and Gianmarco Manzini. A higher order pressure-stabilized virtual element formulation for the stokes-poisson-boltzmann equations. arXiv preprint arXiv:2602.16538, 2026

  7. [7]

    Weak imposition of no-slip conditions in finite element methods

    W Layton. Weak imposition of no-slip conditions in finite element methods. Computers & Mathematics with Applications, 38(5-6):129–142, 1999

  8. [8]

    Finite element approximation on incompressible navier-stokes equations with slip bound- ary condition

    Rüdiger Verfürth. Finite element approximation on incompressible navier-stokes equations with slip bound- ary condition. Numerische Mathematik , 50(6):697–721, 1986

  9. [9]

    The finite element method with penalty

    Ivo Babuška. The finite element method with penalty. Mathematics of computation , 27(122):221–228, 1973

  10. [10]

    Finite element approximation of the dirichlet problem using the boundary penalty method

    John W Barrett and Charles M Elliott. Finite element approximation of the dirichlet problem using the boundary penalty method. Numerische Mathematik , 49(4):343–366, 1986

  11. [11]

    Weak imposition of boundary conditions for the navier–stokes equations by a penalty method

    Atife Caglar and Anastasios Liakos. Weak imposition of boundary conditions for the navier–stokes equations by a penalty method. International journal for numerical methods in fluids , 61(4):411–431, 2009. 26

  12. [12]

    Penalty: finite element approximation of stokes equations with slip boundary conditions

    Ibrahima Dione and José M Urquiza. Penalty: finite element approximation of stokes equations with slip boundary conditions. Numerische Mathematik , 129(3):587–610, 2015

  13. [13]

    Weak imposition of the slip boundary condition on curved boundaries for stokes flow

    José M Urquiza, André Garon, and Marie-Isabelle Farinas. Weak imposition of the slip boundary condition on curved boundaries for stokes flow. Journal of Computational Physics , 256:748–767, 2014

  14. [14]

    Penalty method with p1/p1 finite element approx- imation for the stokes equations under the slip boundary condition

    Takahito Kashiwabara, Issei Oikawa, and Guanyu Zhou. Penalty method with p1/p1 finite element approx- imation for the stokes equations under the slip boundary condition. Numerische Mathematik , 134(4):705– 740, 2016

  15. [15]

    Penalty method for the stationary navier–stokes problems under the slip boundary condition

    Guanyu Zhou, Takahito Kashiwabara, and Issei Oikawa. Penalty method for the stationary navier–stokes problems under the slip boundary condition. Journal of Scientific Computing , 68(1):339–374, 2016

  16. [16]

    Penalty method with crouzeix–raviart approx- imation for the stokes equations under slip boundary condition

    Takahito Kashiwabara, Issei Oikawa, and Guanyu Zhou. Penalty method with crouzeix–raviart approx- imation for the stokes equations under slip boundary condition. ESAIM: Mathematical Modelling and Numerical Analysis, 53(3):869–891, 2019

  17. [17]

    The crouzeix–raviart element for the stokes equations with the slip boundary condition on a curved boundary

    Guanyu Zhou, Issei Oikawa, and Takahito Kashiwabara. The crouzeix–raviart element for the stokes equations with the slip boundary condition on a curved boundary. Journal of Computational and Applied Mathematics, 383:113123, 2021

  18. [18]

    Über ein variationsprinzip zur lösung von dirichlet-problemen bei verwendung von teil- räumen, die keinen randbedingungen unterworfen sind

    Joachim Nitsche. Über ein variationsprinzip zur lösung von dirichlet-problemen bei verwendung von teil- räumen, die keinen randbedingungen unterworfen sind. In Abhandlungen aus dem mathematischen Seminar der Universität Hamburg , volume 36, pages 9–15. Springer, 1971

  19. [19]

    A review on some discrete variational techniques for the approximation of essential boundary conditions: F

    Franz Chouly. A review on some discrete variational techniques for the approximation of essential boundary conditions: F. chouly. Vietnam Journal of Mathematics , 54(1):73–115, 2026

  20. [20]

    A nitsche cut finite element method for the oseen problem with general navier boundary conditions

    M Winter, Benedikt Schott, Andre Massing, and Wolfgang A Wall. A nitsche cut finite element method for the oseen problem with general navier boundary conditions. Computer Methods in Applied Mechanics and Engineering , 330:220–252, 2018

  21. [21]

    Nitsches method for general boundary conditions

    Mika Juntunen and Rolf Stenberg. Nitsches method for general boundary conditions. Mathematics of computation, 78(267):1353–1374, 2009

  22. [22]

    Nitsches method for navier–stokes equations with slip boundary conditions

    Ingeborg Gjerde and L Scott. Nitsches method for navier–stokes equations with slip boundary conditions. Mathematics of Computation , 91(334):597–622, 2022

  23. [23]

    Stokes problem with slip boundary conditions using stabilized finite elements combined with nitsche

    Rodolfo Araya, Alfonso Caiazzo, and Franz Chouly. Stokes problem with slip boundary conditions using stabilized finite elements combined with nitsche. Computer Methods in Applied Mechanics and Engineering , 427:117037, 2024

  24. [24]

    Equal-order stabi- lized finite elements with nitsche for the stationary navier-stokes problem with slip boundary conditions

    Aparna Bansal, Nicolás A Barnafi, Rodolfo Araya, and Dwijendra Narain Pandey. Equal-order stabi- lized finite elements with nitsche for the stationary navier-stokes problem with slip boundary conditions. Computer Methods in Applied Mechanics and Engineering , 450:118578, 2026

  25. [25]

    Nitsche method for navier–stokes equa- tions with slip boundary conditions: convergence analysis and vms-les stabilization

    Aparna Bansal, Nicolás A Barnafi, and Dwijendra Narain Pandey. Nitsche method for navier–stokes equa- tions with slip boundary conditions: convergence analysis and vms-les stabilization. ESAIM: Mathematical Modelling and Numerical Analysis , 58(5):2079–2115, 2024

  26. [26]

    P. A. Gazca-Orozco, F. Gmeineder, E. M. Kokavcová, and T. Tscherpel. A Nitsche method for incompress- ible fluids with general dynamic boundary conditions. ArXiv preprint, arXiv:2502.09550, 2025. Preprint

  27. [27]

    A posteriori error estimation in finite element analysis

    Mark Ainsworth and J Tinsley Oden. A posteriori error estimation in finite element analysis. Computer methods in applied mechanics and engineering , 142(1-2):1–88, 1997

  28. [28]

    A posteriori error estimation techniques for finite element methods

    Rüdiger Verfürth. A posteriori error estimation techniques for finite element methods . OUP Oxford, Oxford, 2013

  29. [29]

    Divergence-conforming methods for transient double-diffusive flows: a priori and a posteriori error analysis

    Raimund Bürger, Arbaz Khan, Paul E Méndez, and Ricardo Ruiz-Baier. Divergence-conforming methods for transient double-diffusive flows: a priori and a posteriori error analysis. IMA Journal of Numerical Analysis, 44(6):3520–3572, 2024

  30. [30]

    Stabilized finite element approximations for a generalized boussinesq problem: a posteriori error analysis

    Alejandro Allendes, César Naranjo, and Enrique Otárola. Stabilized finite element approximations for a generalized boussinesq problem: a posteriori error analysis. Computer Methods in Applied Mechanics and Engineering, 361:112703, 2020. 27

  31. [31]

    An adaptive residual local projection finite element method for the navier–stokes equations

    Rodolfo Araya, Abner H Poza, and Frédéric Valentin. An adaptive residual local projection finite element method for the navier–stokes equations. Advances in Computational Mathematics , 40(5):1093–1119, 2014

  32. [32]

    Adaptive discretization of stationary and incompressible navier–stokes equations by stabilized finite element methods

    Stefano Berrone. Adaptive discretization of stationary and incompressible navier–stokes equations by stabilized finite element methods. Computer methods in applied mechanics and engineering , 190(34):4435– 4455, 2001

  33. [33]

    Kashiwabara, I

    T. Kashiwabara, I. Oikawa, and G. Zhou. Penalty method with Crouzeix-Raviart approximation for the Stokes equations under slip boundary condition. ESAIM: Mathematical Modelling and Numerical Analysis , 53(3):869–891, 2019

  34. [34]

    Theory and practice of finite elements , volume 159 of Applied Mathematical Sciences

    Alexandre Ern and Jean-Luc Guermond. Theory and practice of finite elements , volume 159 of Applied Mathematical Sciences. Springer, New York, 2004

  35. [35]

    Mixed finite element methods and applications , volume 44

    Daniele Boffi, Franco Brezzi, and Michel Fortin. Mixed finite element methods and applications , volume 44. Springer, Berlin, 2013

  36. [36]

    Linear and nonlinear functional analysis with applications

    Philippe G Ciarlet. Linear and nonlinear functional analysis with applications . SIAM, Philadelphia, PA, 2025

  37. [37]

    On some techniques for approximating boundary conditions in the finite element method

    Rolf Stenberg. On some techniques for approximating boundary conditions in the finite element method. Journal of Computational and applied Mathematics , 63(1-3):139–148, 1995

  38. [38]

    Finite Elements I: Approximation and Interpolation , volume 72 of Texts in Applied Mathematics

    Alexandre Ern and Jean-Luc Guermond. Finite Elements I: Approximation and Interpolation , volume 72 of Texts in Applied Mathematics . Springer, Switzerland, 2021

  39. [39]

    The mathematical theory of finite element methods

    Susanne C Brenner and L Ridgway Scott. The mathematical theory of finite element methods . Springer, New York, 2008

  40. [40]

    Robust a posteriori error estimates for stationary convection-diffusion equations

    Rüdiger Verfürth. Robust a posteriori error estimates for stationary convection-diffusion equations. SIAM journal on numerical analysis , 43(4):1766–1782, 2005

  41. [41]

    The fenics project version 1.5

    Martin Alnæs, Jan Blechta, Johan Hake, August Johansson, Benjamin Kehlet, Anders Logg, Chris Richard- son, Johannes Ring, Marie E Rognes, and Garth N Wells. The fenics project version 1.5. Archive of numerical software, 3(100), 2015

  42. [42]

    Mumps: a general purpose distributed memory sparse solver

    Patrick R Amestoy, Iain S Duff, Jean-Yves LExcellent, and Jacko Koster. Mumps: a general purpose distributed memory sparse solver. In International Workshop on Applied Parallel Computing , pages 121–