Abstract
We establish a general approximations theorem for semiconvex and semiconcave functions with general modulus by using the compensated convex transforms introduced by K. Zhang [Compensated convexity and its applications, Ann. Inst. H. Poincaré (C) Non Linear Analysis 25/4 (2008) 743–771]. For a semiconvex function with general modulus, we show that the limit of the gradient of the upper compensated transform exists and is equal to the center of the minimal bounding sphere in the sense of H. Jung [Über die kleinste Kugel, die eine räumliche Figur einschlie{ß}t, J. Reine Angew. Mathematik 123 (1901) 241–257] of the Fréchet sub\-differential. We also prove a regularity result for the upper transform of semiconvex functions with general modulus.
References
- M. S. Alatawi: The locality property for compensated convex transforms, J. Convex Analysis 29/4 (2022) 1037–1064.https://doi.org/10.68381/jca29059Google Scholar
- M. Alatawi, K. Zhang: Hausdorff stability and error estimates for compensated convexity based methods for approximation and interpolation for functions in rn, J. Convex Analysis 27/4 (2020) 1277–1302.https://doi.org/10.68381/jca27068Google Scholar
- G. Alberti, L. Ambrosio, P. Cannarsa: On the singularities of convex functions, Manuscripta Math. 76/1 (1992) 421–435.https://doi.org/10.1007/BF02567770Google Scholar
- J. M. Ball, B. Kirchheim, J. Kristensen: Regularity of quasiconvex envelopes, Calc. Var. Partial Diff. Equations 11/4 (2000) 333–359.https://doi.org/10.1007/s005260000041Google Scholar
- P. Cannarsa, C. Sinestrari: Semiconcave Functions, Hamilton-Jacobi Equations, and Optimal Control, Birkhäuser, Basel (2004).https://doi.org/10.1007/b138356Google Scholar
- F. H. Clarke: Generalized gradients and applications, Trans. Amer. Math. Soc. 205 (1975) 247–262.https://doi.org/10.1090/S0002-9947-1975-0367131-6Google Scholar
- B. Dacorogna: Direct Methods in the Calculus of Variations, Springer, Berlin (1989).https://doi.org/10.1007/978-3-642-51440-1Google Scholar
- R. A. DeVore, G. G. Lorentz: Constructive Approximation, Springer, Berlin (1993).https://doi.org/10.1007/978-3-662-02888-9Google Scholar
- D. Gilbarg, N. S. Trudinger: Elliptic Partial Differential Equations of Second Order, Springer, Berlin (1983).Google Scholar
- J.-B. Hiriart-Urruty, C. Lemaréchal: Fundamentals of Convex Analysis, Springer, Berlin (2001).https://doi.org/10.1007/978-3-642-56468-0Google Scholar
- H. Jung: Über die kleinste Kugel, die eine räumliche Figur einschließt, J. Reine Angew. Math. 123 (1901) 241–257.https://doi.org/10.1515/crll.1901.123.241Google Scholar
- B. Kirchheim, J. Kristensen: Differentiability of convex envelopes, C. R. Acad. Sci. Ser. I Math. 333/8 (2001) 725–728.https://doi.org/10.1016/S0764-4442(01)02117-6Google Scholar
- J. M. Lasry, P. L. Lions: A remark on regularization in Hilbert spaces, Israel J. Math. 55 (1986) 257–266.https://doi.org/10.1007/BF02765025Google Scholar
- R. T. Rockafellar: Convex Analysis, Princeton University Press, Princeton (1970).https://doi.org/10.1515/9781400873173Google Scholar
- L. Thibault: Unilateral Variational Analysis in Banach Spaces. Part I: General Theory, World Scientific Publishing, Singapore (2023).https://doi.org/10.1142/12797Google Scholar
- L. Thibault: Unilateral Variational Analysis in Banach Spaces. Part II: Special Classes of Functions and Sets, World Scientific Publishing, Singapore (2023).https://doi.org/10.1142/12797Google Scholar
- K. Zhang: Compensated convexity and its applications, Ann. Inst. H. Poincaré (C) Non Linear Analysis 25/4 (2008) 743–771.https://doi.org/10.1016/j.anihpc.2007.08.001Google Scholar
- K. Zhang, A. Orlando, E. Crooks: Compensated convexity methods for approximations and interpolations of sampled functions in euclidean spaces: Theoretical foundations, SIAM J. Math. Analysis 48/6 (2016) 4126–4154.https://doi.org/10.1137/15M1045673Google Scholar
- K. Zhang, A. Orlando, E. Crooks: Compensated convexity and Hausdorff stable geometric singularity extractions, Math. Models Meth. Appl. Sci. 25/4 (2015) 747–801.https://doi.org/10.1142/S0218202515500189Google Scholar
- K. Zhang, A. Orlando, E. Crooks: Compensated convexity and Hausdorff stable extraction of intersections for smooth manifolds, Math. Models Meth. Appl. Sci. 25/5 (2015) 839–873.https://doi.org/10.1142/S0218202515500207Google Scholar
- K. Zhang, A. Orlando, E. Crooks: Compensated convex transforms and geometric singularity extraction from semiconvex functions, Sci. Sinica Math. 46/5 (2016) 747–768.Google Scholar
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Published by Heldermann Verlag, 2024. Rights now held by Banach Press LLC.
