pith. sign in

arxiv: 2605.00635 · v1 · submitted 2026-05-01 · 🧮 math.AP

Nonlocal Approximation Principle for Entropy Solutions of Scalar Conservation Laws

Pith reviewed 2026-05-09 19:11 UTC · model grok-4.3

classification 🧮 math.AP MSC 35L6535D40
keywords entropy solutionsscalar conservation lawsnonlocal approximationHamilton-Jacobi equationsviscosity solutionsweak-star convergencefinite propagation speed
0
0 comments X

The pith

The entropy solution to a scalar conservation law with nonnegative initial data arises as the weak-star limit of solutions to a nonlocal conservation law whose flux uses spatial averages of the density.

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

The paper shows that entropy solutions of scalar conservation laws can be recovered as limits of nonlocal approximations in which the flux is evaluated on spatial averages of the density rather than pointwise values. For nonnegative initial data this limit is the unique entropy solution, obtained by first integrating the equation to reach a Hamilton-Jacobi problem, passing to the limit with the stability theory for viscosity solutions, and then differentiating back. The same construction works for sign-changing data after a shift, and quantitative convergence rates are proved when the flux is convex. The result supplies a way to define entropy solutions for general fluxes through nonlocal models that automatically obey finite speed of propagation.

Core claim

The entropy solution to a nonnegative initial datum can be obtained as a weak-star limit of a corresponding scalar nonlocal conservation law. The flux function of the nonlocal conservation law depends on suitable spatial averages of the density. The proof is based on a reformulation on the Hamilton–Jacobi level: working with the primitives, the limit is identified via the stability properties of viscosity solutions and the entropy solution is recovered using the classical relation between Hamilton–Jacobi equations and scalar conservation laws. The approximation extends, after a suitable shift, to sign-changing initial data, and quantitative convergence estimates are proved for convex fluxes.

What carries the argument

Integration of the conservation law to a Hamilton–Jacobi equation whose Hamiltonian is formed from spatial averages of the density, followed by passage to the limit via viscosity-solution stability.

If this is right

  • Entropy solutions for general fluxes can be defined as weak-star limits of nonlocal approximations that obey finite propagation speed.
  • Quantitative rates of convergence to the entropy solution are available whenever the flux is convex, measured by the first moments of the averaging kernels.
  • The same nonlocal construction yields the entropy solution for sign-changing initial data after a constant shift.
  • Nonlocal models with averaging kernels furnish a class of regularized equations whose limits automatically satisfy the entropy condition.

Where Pith is reading between the lines

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

  • The averaging approach may supply an alternative route to existence of entropy solutions that avoids direct application of Kružkov’s doubling-variables argument.
  • If analogous nonlocal fluxes can be defined for systems, the same viscosity-stability argument could extend the approximation principle beyond scalar equations.
  • Numerical schemes based on the nonlocal equations might converge to the correct entropy solution without adding artificial viscosity.

Load-bearing premise

The nonlocal kernels must satisfy integrability and approximation properties that make the spatial averages converge to the local density value, and the initial datum must be nonnegative or shiftable to a nonnegative function.

What would settle it

A concrete flux and initial datum for which a sequence of nonlocal solutions with kernels whose first moments go to zero fails to converge weak-star to the entropy solution or violates the entropy inequality in the limit.

read the original abstract

We establish a general nonlocal approximation principle for the entropy solutions of scalar conservation laws on $\mathbb{R}$. More precisely, we show that the entropy solution to a nonnegative initial datum can be obtained as a weak-star limit of a corresponding scalar nonlocal conservation law. The flux function of the nonlocal conservation law depends on suitable spatial averages of the density. The proof is based on a reformulation on the Hamilton--Jacobi level: working with the primitives, we identify the limit via the stability properties of viscosity solutions; we then recover the entropy solution using the classical relation between Hamilton--Jacobi equations and scalar conservation laws. We further show that the approximation extends, after a suitable shift, to sign-changing initial data, and we prove a quantitative convergence estimate for convex fluxes in terms of the first moments of the nonlocal kernels. This result makes it possible to define entropy solutions for general fluxes using their nonlocal approximations, which satisfy the requirement for a finite speed of mass propagation, a key feature of hyperbolic conservation laws.

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

0 major / 2 minor

Summary. The manuscript establishes a nonlocal approximation principle for entropy solutions of scalar conservation laws on the real line. For nonnegative initial data, the entropy solution is recovered as the weak-star limit of solutions to a corresponding nonlocal conservation law whose flux depends on spatial averages of the density. The proof lifts the problem to the Hamilton-Jacobi level, invokes stability of viscosity solutions to identify the limit, and recovers the entropy solution via the classical integral relation between HJ equations and conservation laws. The result extends to sign-changing data after a constant shift, and a quantitative convergence estimate is given for convex fluxes in terms of the first moments of the nonlocal kernels.

Significance. If the result holds, it supplies a principled way to define or approximate entropy solutions for general fluxes by means of nonlocal models that automatically satisfy finite speed of mass propagation. The argument rests on well-established stability theorems for viscosity solutions and the standard entropy-viscosity correspondence, which lends it technical reliability. The quantitative rate for convex fluxes and the extension to sign-changing data are useful additions that broaden applicability.

minor comments (2)
  1. The hypotheses on the nonlocal kernels (integrability, approximation to the identity, and moment conditions) are stated in several places; collecting them into a single, clearly labeled assumption block would improve readability.
  2. In the quantitative estimate for convex fluxes, the dependence on the first moment of the kernel is stated but the precise constant in the rate is not tracked explicitly; adding this constant would make the bound easier to use in applications.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of the manuscript, the clear summary of its contributions, and the recommendation to accept. There are no major comments to address.

Circularity Check

0 steps flagged

No significant circularity; derivation uses independent external theorems

full rationale

The central argument reformulates the nonlocal problem as a Hamilton-Jacobi equation, invokes standard stability of viscosity solutions to pass to the weak-star limit, and recovers the entropy solution via the classical integral relation between HJ and conservation laws. Kernel integrability/approximation-to-delta conditions are explicit hypotheses ensuring pointwise convergence of averages; nonnegativity (or shift) is used only for comparison principles. No step reduces the target entropy solution to a fitted parameter, self-definition, or self-citation chain. All load-bearing steps rely on externally verifiable facts (viscosity stability, HJ-conservation relation) that do not presuppose the paper's result.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on two standard background results from PDE theory and introduces no free parameters or new entities.

axioms (2)
  • standard math Stability of viscosity solutions to Hamilton-Jacobi equations under suitable limits
    Invoked to identify the limit of the nonlocal primitives.
  • standard math Classical equivalence between entropy solutions of scalar conservation laws and viscosity solutions of the associated Hamilton-Jacobi equation via integration
    Used to recover the entropy solution from the limiting Hamilton-Jacobi solution.

pith-pipeline@v0.9.0 · 5464 in / 1275 out tokens · 43106 ms · 2026-05-09T19:11:00.098164+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

55 extracted references · 55 canonical work pages

  1. [1]

    Mathematics of Computation34(149), 45–75 (1980) https://doi.org/10.1090/S0025-5718-1980-0551290-1

    Engquist, B., Osher, S.: Stable and entropy satisfying approximations for tran- sonic flow calculations. Mathematics of Computation34(149), 45–75 (1980) https://doi.org/10.1090/S0025-5718-1980-0551290-1

  2. [2]

    Journal of Differential Equations263(7), 4023–4069 (2017) https: //doi.org/10.1016/j.jde.2017.05.015

    Keimer, A., Pflug, L.: Existence, uniqueness and regularity results on nonlocal balance laws. Journal of Differential Equations263(7), 4023–4069 (2017) https: //doi.org/10.1016/j.jde.2017.05.015

  3. [3]

    Comptes Rendus

    Keimer, A., Pflug, L.: Discontinuous nonlocal conservation laws and related dis- continuous ODEs – Existence, Uniqueness, Stability and Regularity. Comptes Rendus. Math´ ematique361(G11), 1723–1760 (2023) https://doi.org/10.5802/ crmath.490 20

  4. [4]

    arXiv (2025)

    Friedrich, J., Herty, M., Nocita, C.: Control of Conservation Laws in the Nonlocal- to-Local Limit. arXiv (2025). https://doi.org/10.48550/ARXIV.2510.00677 . https://arxiv.org/abs/2510.00677

  5. [5]

    arXiv (2025)

    Keimer, A., Pflug, L., Rodestock, J.: Optimal Control Problems with Nonlocal Conservation Laws: Existence of Optimizers and Singular Limits in Approxi- mations of Local Conservation Laws. arXiv (2025). https://doi.org/10.48550/ ARXIV.2512.17870 . https://arxiv.org/abs/2512.17870

  6. [6]

    Viet- nam Journal of Mathematics49(3), 957–985 (2021) https://doi.org/10.1007/ s10013-021-00506-7

    Bayen, A., Coron, J.-M., De Nitti, N., Keimer, A., Pflug, L.: Boundary con- trollability and asymptotic stabilization of a nonlocal traffic flow model. Viet- nam Journal of Mathematics49(3), 957–985 (2021) https://doi.org/10.1007/ s10013-021-00506-7

  7. [7]

    Coral: Concept drift representa- tion learning for co-evolving time-series

    Coclite, G.M., Karlsen, K.H., Risebro, N.H.: Upwind filtering of scalar con- servation laws. arXiv:2501.18340v2 (2025). https://doi.org/10.48550/arXiv.2501. 18340

  8. [8]

    Inventiones Mathematicae98(3), 511–547 (1989) https://doi.org/ 10.1007/bf01393835

    DiPerna, R.J., Lions, P.L.: Ordinary differential equations, transport theory and sobolev spaces. Inventiones Mathematicae98(3), 511–547 (1989) https://doi.org/ 10.1007/bf01393835

  9. [9]

    On the numerical integration of scalar nonlocal conservation laws

    Amorim, P., Colombo, R.M., Teixeira, A.: On the numerical integration of scalar nonlocal conservation laws. ESAIM: Mathematical Modelling and Numerical Analysis49(1), 19–37 (2015) https://doi.org/10.1051/m2an/2014023

  10. [10]

    Quarterly of Applied Mathematics57(3), 573–600 (1999)

    Zumbrun, K.: On a nonlocal dispersive equation modeling particle suspensions. Quarterly of Applied Mathematics57(3), 573–600 (1999)

  11. [11]

    Well-posedness of a conservation law with non-local flux arising in traffic flow modeling

    Blandin, S., Goatin, P.: Well-posedness of a conservation law with non-local flux arising in traffic flow modeling. Numerische Mathematik132(2), 217–241 (2015) https://doi.org/10.1007/s00211-015-0717-6

  12. [12]

    Well-posedness and finite volume approximations of the LWR traffic flow model with non-local velocity

    Goatin, P., Scialanga, S.: Well-posedness and finite volume approximations of the lwr traffic flow model with non-local velocity. Networks and Heterogeneous Media 11(1), 107–121 (2016) https://doi.org/10.3934/nhm.2016.11.107

  13. [13]

    On approximation of local conservation laws by nonlocal conservation laws

    Keimer, A., Pflug, L.: On approximation of local conservation laws by nonlocal conservation laws. Journal of Mathematical Analysis and Applications475(2), 1927–1955 (2019) https://doi.org/10.1016/j.jmaa.2019.03.063

  14. [14]

    Archive for Rational Mechanics and Analysis 233(3), 1131–1167 (2019) https://doi.org/10.1007/s00205-019-01375-8

    Colombo, M., Crippa, G., Spinolo, L.V.: On the singular local limit for conser- vation laws with nonlocal fluxes. Archive for Rational Mechanics and Analysis 233(3), 1131–1167 (2019) https://doi.org/10.1007/s00205-019-01375-8

  15. [15]

    Nonlinear Analysis211, 112370 (2021) 21 https://doi.org/10.1016/j.na.2021.112370

    Coclite, G.M., De Nitti, N., Keimer, A., Pflug, L.: Singular limits with vanishing viscosity for nonlocal conservation laws. Nonlinear Analysis211, 112370 (2021) 21 https://doi.org/10.1016/j.na.2021.112370

  16. [16]

    ESAIM: Mathematical Modelling and Numerical Analysis55(6), 2705–2723 (2021) https: //doi.org/10.1051/m2an/2021073

    Colombo, M., Crippa, G., Graff, M., Spinolo, L.V.: On the role of numerical viscosity in the study of the local limit of nonlocal conservation laws. ESAIM: Mathematical Modelling and Numerical Analysis55(6), 2705–2723 (2021) https: //doi.org/10.1051/m2an/2021073

  17. [17]

    Archive for Rational Mechanics and Analysis237(3), 1213–1236 (2020) https://doi.org/10.1007/s00205-020-01529-z

    Bressan, A., Shen, W.: On traffic flow with nonlocal flux: A relaxation represen- tation. Archive for Rational Mechanics and Analysis237(3), 1213–1236 (2020) https://doi.org/10.1007/s00205-020-01529-z

  18. [18]

    Annales de l’Institut Henri Poincar´ e C, Analyse non lin´ eaire38(5), 1653–1666 (2021) https://doi.org/10.1016/j.anihpc.2020.12.002

    Crippa, G., Marconi, E., Spinolo, L.V., Colombo, M.: Local limit of nonlo- cal traffic models: Convergence results and total variation blow-up. Annales de l’Institut Henri Poincar´ e C, Analyse non lin´ eaire38(5), 1653–1666 (2021) https://doi.org/10.1016/j.anihpc.2020.12.002

  19. [19]

    Entropy admissibility of the limit solution for a nonlocal model of traffic flow

    Bressan, A., Shen, W.: Entropy admissibility of the limit solution for a nonlocal model of traffic flow. Communications in Mathematical Sciences19(5), 1447–1450 (2021) https://doi.org/10.4310/cms.2021.v19.n5.a12

  20. [20]

    Annales de l’Institut Henri Poincar´ e C, Analyse non lin´ eaire40(5), 1205–1223 (2022) https://doi.org/10

    Coclite, G.M., Coron, J.-M., De Nitti, N., Keimer, A., Pflug, L.: A general result on the approximation of local conservation laws by nonlocal conservation laws: The singular limit problem for exponential kernels. Annales de l’Institut Henri Poincar´ e C, Analyse non lin´ eaire40(5), 1205–1223 (2022) https://doi.org/10. 4171/aihpc/58

  21. [21]

    Archive for Rational Mechanics and Analysis247(2) (2023) https://doi.org/10

    Colombo, M., Crippa, G., Marconi, E., Spinolo, L.V.: Nonlocal traffic models with general kernels: Singular limit, entropy admissibility, and convergence rate. Archive for Rational Mechanics and Analysis247(2) (2023) https://doi.org/10. 1007/s00205-023-01845-0

  22. [22]

    Journ´ ees ´ equations aux d´ eriv´ ees partielles, 1–14 (2024) https://doi.org/10.5802/ jedp.681

    Colombo, M., Crippa, G., Marconi, E., Spinolo, L.V.: An overview on the local limit of non-local conservation laws, and a new proof of a compactness estimate. Journ´ ees ´ equations aux d´ eriv´ ees partielles, 1–14 (2024) https://doi.org/10.5802/ jedp.681

  23. [23]

    Journal of Mathematical Analysis and Applications547(2), 129307 (2025) https://doi.org/ 10.1016/j.jmaa.2025.129307

    Keimer, A., Pflug, L.: On the singular limit problem for nonlocal conservation laws: A general approximation result for kernels with fixed support. Journal of Mathematical Analysis and Applications547(2), 129307 (2025) https://doi.org/ 10.1016/j.jmaa.2025.129307

  24. [24]

    Lusternik-Schnirelman and Morse theory for the van der Waals-Cahn-Hilliard equation with volume constraint

    Keimer, A., Pflug, L.: On the singular limit problem for a discontinuous nonlo- cal conservation law. Nonlinear Analysis237, 113381 (2023) https://doi.org/10. 1016/j.na.2023.113381

  25. [25]

    Journal of Math- ematical Analysis and Applications537(2), 128358 (2024) https://doi.org/10

    Chiarello, F.A., Keimer, A.: On the singular limit problem in nonlocal balance 22 laws: Applications to nonlocal lane-changing traffic flow models. Journal of Math- ematical Analysis and Applications537(2), 128358 (2024) https://doi.org/10. 1016/j.jmaa.2024.128358

  26. [26]

    arXiv (2025)

    De Nitti, N., Huang, K.: A Volterra equation approach to the local limit of non- local traffic models. arXiv (2025). https://doi.org/10.48550/ARXIV.2512.06805 . https://arxiv.org/abs/2512.06805

  27. [27]

    arXiv (2025)

    Coclite, G.M., De Nitti, N., Huang, K.: Singular limit for a class of nonlocal conservation laws via compensated compactness. arXiv (2025). https://doi.org/ 10.48550/ARXIV.2511.15631 . https://arxiv.org/abs/2511.15631

  28. [28]

    In: Knops, R.J

    Tartar, L.: Compensated compactness and applications to partial differential equations. In: Knops, R.J. (ed.) Nonlinear Analysis and Mechanics: Heriot-Watt Symposium, Vol. IV. Research Notes in Mathematics, vol. 39, pp. 136–212. Pitman, Boston (1979)

  29. [29]

    Uspekhi Mat

    Oleinik, O.A.: Discontinuous solutions of non-linear differential equations. Uspekhi Mat. Nauk12, 3–73 (1957)

  30. [30]

    In: Sev- enteen Papers on Analysis

    Ole˘ ınik, O.A.: Discontinuous solutions of non-linear differential equations. In: Sev- enteen Papers on Analysis. American Mathematical Society Translations, Series 2, vol. 26, pp. 95–172. American Mathematical Society, Providence, RI (1963)

  31. [31]

    Journal of Hyperbolic Differential Equations21(03), 681–705 (2024) https://doi.org/10.1142/s021989162440006x

    Coclite, G.M., Colombo, M., Crippa, G., De Nitti, N., Keimer, A., Marconi, E., Pflug, L., Spinolo, L.V.: Oleinik-type estimates for nonlocal conservation laws and applications to the nonlocal-to-local limit. Journal of Hyperbolic Differential Equations21(03), 681–705 (2024) https://doi.org/10.1142/s021989162440006x

  32. [32]

    SIAM Journal on Numerical Analysis62(3), 1119–1144 (2024) https://doi.org/10.1137/23m154488x

    Huang, K., Du, Q.: Asymptotic compatibility of a class of numerical schemes for a nonlocal traffic flow model. SIAM Journal on Numerical Analysis62(3), 1119–1144 (2024) https://doi.org/10.1137/23m154488x

  33. [33]

    arXiv (2025)

    De Nitti, N., Huang, K.: Asymptotically compatible entropy-consistent discretiza- tion for a class of nonlocal conservation laws. arXiv (2025). https://doi.org/10. 48550/ARXIV.2510.00221 . https://arxiv.org/abs/2510.00221

  34. [34]

    Discrete and Continuous Dynamical Systems43(9), 3456–3484 (2023) https://doi.org/10.3934/dcds.2023054

    Du, Q., Huang, K., Scott, J., Shen, W.: A space-time nonlocal traffic flow model: Relaxation representation and local limit. Discrete and Continuous Dynamical Systems43(9), 3456–3484 (2023) https://doi.org/10.3934/dcds.2023054

  35. [35]

    arXiv (2025)

    Chiarello, F.A., Keimer, A., Pflug, L.: Nonlocal conservation laws with p-norm, the singular limit problem and applications to traffic flow. arXiv (2025). https: //doi.org/10.48550/ARXIV.2512.18701 . https://arxiv.org/abs/2512.18701

  36. [36]

    SIAM 23 Journal on Mathematical Analysis52(6), 5500–5532 (2020) https://doi.org/10

    Coron, J.-M., Keimer, A., Pflug, L.: Nonlocal transport equations—existence and uniqueness of solutions and relation to the corresponding conservation laws. SIAM 23 Journal on Mathematical Analysis52(6), 5500–5532 (2020) https://doi.org/10. 1137/20m1331652

  37. [37]

    Networks and Heterogeneous Media 20(4), 1061–1086 (2025) https://doi.org/10.3934/nhm.2025046

    Ghoshal, S.S., Venkatesh, P., Wiedemann, E.: A non-conservative, non-local approximation of the burgers equation. Networks and Heterogeneous Media 20(4), 1061–1086 (2025) https://doi.org/10.3934/nhm.2025046

  38. [38]

    Journal of Physics A: Mathematical and Theoretical41(34), 344016 (2008) https://doi.org/10.1088/1751-8113/41/34/344016

    Norgard, G., Mohseni, K.: A regularization of the burgers equation using a filtered convective velocity. Journal of Physics A: Mathematical and Theoretical41(34), 344016 (2008) https://doi.org/10.1088/1751-8113/41/34/344016

  39. [39]

    In: Ancona, F., Bressan, A., Marcati, P., Marson, A

    Risebro, N.H., Weber, F.: Hyperbolic problems: theory, numerics, applications. In: Ancona, F., Bressan, A., Marcati, P., Marson, A. (eds.) Proceedings of the 14th International Conference (HYP2012) Held in Padova, June 25–29, 2012. AIMS Series on Applied Mathematics, vol. 8, pp. 1031–1038. American Institute of Mathematical Sciences (AIMS), Springfield, MO (2014)

  40. [40]

    Bressan, A.: Hyperbolic Systems of Conservation Laws, p. 250. Oxford University Press, Oxford (2000)

  41. [41]

    Eymard, T

    Eymard, R., Gallou¨ et, T., Herbin, R.: Finite volume methods. In: Solution of Equation inR n (Part 3), Techniques of Scientific Computing (Part 3). Handbook of Numerical Analysis, vol. 7, pp. 713–1020. Elsevier, Amsterdam (2000). https: //doi.org/10.1016/S1570-8659(00)07005-8

  42. [42]

    Mathematics of the USSR-Sbornik10(2), 217–243 (1970) https://doi.org/10

    Kruˇ zkov, S.N.: First order quasilinear equations in several independent variables. Mathematics of the USSR-Sbornik10(2), 217–243 (1970) https://doi.org/10. 1070/sm1970v010n02abeh002156

  43. [43]

    Math´ ematiques & applications

    Godlewski, E., Raviart, P.A.: Hyperbolic Systems of Conservation Laws. Math´ ematiques & applications. Ellipses, Paris (1991)

  44. [44]

    , year =

    Dafermos, C.M.: Hyperbolic Conservation Laws in Continuum Physics, 4th edn. Grundlehren der mathematischen Wissenschaften, vol. 325. Springer, Berlin, Heidelberg (2016). https://doi.org/10.1007/978-3-662-49451-6

  45. [45]

    Graduate Studies in Mathematics, vol

    Evans, L.C.: Partial Differential Equations. Graduate Studies in Mathematics, vol. 19, p. 749. American Mathematical Society, Providence RI (2007)

  46. [46]

    Nonlinear Analysis: Theory, Methods & Applications 10(4), 353–370 (1986) https://doi.org/10.1016/0362-546x(86)90133-1

    Crandall, M.G., Lions, P.-L.: On existence and uniqueness of solutions of Hamilton-Jacobi equations. Nonlinear Analysis: Theory, Methods & Applications 10(4), 353–370 (1986) https://doi.org/10.1016/0362-546x(86)90133-1

  47. [47]

    Research Notes in Mathematics, vol

    Lions, P.-L.: Generalized Solutions of Hamilton–Jacobi Equations. Research Notes in Mathematics, vol. 69. Pitman, Boston, London, Melbourne (1982)

  48. [48]

    Nonlinear Analysis: Theory, Methods & Applications 50(4), 455–469 (2002) https://doi.org/10.1016/s0362-546x(01)00753-2

    Karlsen, K.H., Risebro, N.H.: A note on front tracking and the equivalence 24 between viscosity solutions of hamilton–jacobi equations and entropy solutions of scalar conservation laws. Nonlinear Analysis: Theory, Methods & Applications 50(4), 455–469 (2002) https://doi.org/10.1016/s0362-546x(01)00753-2

  49. [49]

    Bardi, and I

    Bardi, M., Capuzzo-Dolcetta, I.: Optimal Control and Viscosity Solutions of Hamilton-Jacobi-Bellman Equations. Modern Birkh¨ auser Classics. Birkh¨ auser Boston, Boston, MA (2009). https://doi.org/10.1007/978-0-8176-4755-1 . Orig- inally published in 1997 in the series Systems & Control: Foundations & Applications

  50. [50]

    (eds.) Pure and Applied Mathematics, vol

    Adams, R.A., Fournier, J.J.F. (eds.) Pure and Applied Mathematics, vol. 140. Elsevier (2003)

  51. [51]

    Oliver and Boyd, Edinburgh and London (1963)

    Berge, C.: Topological Spaces: Including a Treatment of Multi-Valued Functions, Vector Spaces and Convexity. Oliver and Boyd, Edinburgh and London (1963)

  52. [52]

    SIAM Journal on Applied Mathematics 84(2), 497–522 (2024) https://doi.org/10.1137/22m1530471

    Friedrich, J., G¨ ottlich, S., Keimer, A., Pflug, L.: Conservation laws with nonlocal velocity: The singular limit problem. SIAM Journal on Applied Mathematics 84(2), 497–522 (2024) https://doi.org/10.1137/22m1530471

  53. [53]

    Progress in Nonlinear Differential Equations and Their Applications, vol

    Cannarsa, P., Sinestrari, C.: Semiconcave Functions, Hamilton-Jacobi Equations, and Optimal Control. Progress in Nonlinear Differential Equations and Their Applications, vol. 58. Birkh¨ auser, Boston (2004). https://doi.org/10.1007/ 978-0-8176-4584-2

  54. [54]

    Princeton Mathematical Series, vol

    Rockafellar, R.T.: Convex Analysis. Princeton Mathematical Series, vol. 28. Princeton University Press, Princeton, NJ (1970)

  55. [55]

    Springer, New York (2011)

    Brezis, H.: Functional Analysis, Sobolev Spaces and Partial Differen- tial Equations. Springer, New York (2011). https://doi.org/10.1007/ 978-0-387-70914-7 25