On a convex bounded open set, we prove that Poincaré-Sobolev constants for functions vanishing at the boundary can be bounded from below in terms of the norm of the distance function in a suitable Lebesgue space. This generalizes a result shown, in the planar case, by E. Makai, for the torsional rigidity. In addition, we compare the sharp Makai constants obtained in the class of convex sets with the optimal constants defined in other classes of open sets. Finally, an alternative proof of the Hersch-Protter inequality for convex sets is given.

Contact details are reproduced from the original publication and may be historical.

Francesca Prinari

Dip. di Scienze Agrarie, Alimentari e Agro-Ambientali, Università di Pisa, Pisa, Italy

francesca.prinari@unipi.it

Anna Chiara Zagati

Dip. di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, Parma, Italy

annachiara.zagati@unipr.it
  1. W. Allegretto, Y. X. Huang: A Picone’s identity for the p-Laplacian and applications, Nonlinear Analysis 32 (1998) 819–830.https://doi.org/10.1016/S0362-546X(97)00530-0Google Scholar
  2. A. Ancona: On strong barriers and inequality of Hardy for domains in RN, J. London Math. Soc. (2) 34 (1986) 274–290.https://doi.org/10.1112/jlms/s2-34.2.274Google Scholar
  3. D. H. Armitage, Ü. Kuran: The convexity of a domain and the superharmonicity of the signed distance function, Proc. Amer. Math. Soc. 93 (1985) 598–600.https://doi.org/10.1090/S0002-9939-1985-0776186-8Google Scholar
  4. F. G. Avkhadiev: Hardy type inequalities in higher dimensions with explicit estimate of constants, Lobachevskii J. Math. 21 (2006) 3–31.Google Scholar
  5. M. van den Berg: Estimates for the torsion function and Sobolev constants, Potential Analysis 36 (2012) 607–616.https://doi.org/10.1007/s11118-011-9246-9Google Scholar
  6. L. Brasco: On principal frequencies and inradius in convex sets, Bruno Pini Math. Anal. Semin. 9, Univ. Bologna, Bologna (2018) 78–101.Google Scholar
  7. L. Brasco: On principal frequencies and isoperimetric ratios in convex sets, Ann. Fac. Sci. Toulouse Math. (6) 29 (2020) 977–1005.https://doi.org/10.5802/afst.1653Google Scholar
  8. L. Brasco, D. Mazzoleni: On principal frequencies, volume and inradius in convex sets, Nonlinear Diff. Equations Appl. 27 (2020), art. no. 12, 26p.https://doi.org/10.1007/s00030-019-0614-2Google Scholar
  9. L. Brasco, F. Prinari, A. C. Zagati: A comparison principle for the Lane–Emden equation and applications to geometric estimates, Nonlinear Analysis Theory Methods Appl. Ser. A 220 (2022), art. no. 112847, 41p.https://doi.org/10.1016/j.na.2022.112847Google Scholar
  10. L. Brasco, F. Prinari, A. C. Zagati: Sobolev embeddings and distance functions, Adv. Calc. Variations (2023), to appear, arXiv: 2301.13026 (2023).Google Scholar
  11. L. Briani, G. Buttazzo, F. Prinari: A shape optimization problem on planar sets with prescribed topology, J. Optim. Theory Appl. 193 (2022) 760–784.https://doi.org/10.1007/s10957-021-01870-7Google Scholar
  12. L. Briani, G. Buttazzo, F. Prinari: Inequalities between torsional rigidity and principal eigenvalue of the p-Laplacian, Calc. Var. Partial Diff. Equations 61/2 (2022), art. no. 78, 25p.https://doi.org/10.1007/s00526-021-02129-9Google Scholar
  13. G. Buttazzo, S. Guarino Lo Bianco, M. Marini: Sharp estimates for the anisotropic torsional rigidity and the principal frequency, J. Math. Anal. Appl. 457 (2018) 1153–1172.https://doi.org/10.1016/j.jmaa.2017.03.055Google Scholar
  14. G. Crasta, A. Malusa: The distance function from the boundary in a Minkowski space, Trans. Amer. Math. Soc. 359 (2007) 5725–5759.https://doi.org/10.1090/S0002-9947-07-04260-2Google Scholar
  15. F. Della Pietra, G. Di Blasio N. Gavitone: Sharp estimates on the first Dirichlet eigenvalue of nonlinear elliptic operators via maximum principle, Adv. Nonlinear Analysis 9 (2020) 278–291.https://doi.org/10.1515/anona-2017-0281Google Scholar
  16. F. Della Pietra, N. Gavitone, S. Guarino Lo Bianco: On functionals involving the torsional rigidity related to some classes of nonlinear operators, J. Diff. Equations 265 (2018) 6424–6442.https://doi.org/10.1016/j.jde.2018.07.030Google Scholar
  17. H. G. Eggleston: Convexity, Cambridge Tracts in Mathematics and Mathematical Physics Vol. 47, Cambridge University Press, Cambridge (1958).Google Scholar
  18. D. Goel, Y. Pinchover, G. Psaradakis: On weighted Lp -Hardy inequality on domains in RN, Pure Appl. Funct. Analysis 7/3 (2022) 1025–1023.Google Scholar
  19. J. Hersch: Sur la fréquence fondamentale d’une membrane vibrante: évaluations par défaut et principe de maximum, Z. Angew. Math. Phys. 11 (1960) 387–413.https://doi.org/10.1007/BF01604498Google Scholar
  20. R. Kajikiya: A priori estimate for the first eigenvalue of the p-Laplacian, Diff. Int. Equations 28 (2015) 1011–1028.https://doi.org/10.57262/die/1435064548Google Scholar
  21. J. L. Lewis: Uniformly fat sets, Trans. Amer. Math. Soc. 308 (1988) 177–196.https://doi.org/10.1090/S0002-9947-1988-0946438-4Google Scholar
  22. E. Makai: On the principal frequency of a membrane and the torsional rigidity of a beam, Studies in Math. Analysis and Related Topics, Stanford University Press, Stanford (1962), 227–231.Google Scholar
  23. E. Makai: A lower estimation of the principal frequencies of simply connected membranes, Acta Math. Acad. Sci. Hungaricae 16 (1965) 319–323.https://doi.org/10.1007/BF01904840Google Scholar
  24. M. Marcus, V. J. Mizel, Y. Pinchover: On the best constant for Hardy’s inequality in Rn, Trans. Amer. Math. Soc. 350 (1998) 3237–3255.https://doi.org/10.1090/S0002-9947-98-02122-9Google Scholar
  25. R. Osserman: A note on Hayman’s theorem on the bass note of a drum, Comm. Math. Helvetici 52 (1977) 545–555.https://doi.org/10.1007/BF02567388Google Scholar
  26. M. H. Protter: A lower bound for the fundamental frequency of a convex region, Proc. Amer. Math. Soc. 81 (1981) 65–70.https://doi.org/10.1090/S0002-9939-1981-0589137-2Google Scholar
  27. R. Schneider: Convex Bodies: The Brunn-Minkowski Theory, Encyclopedia of Mathematics and its Applications Vol. 44, Cambridge University Press, Cambridge (1993).https://doi.org/10.1017/CBO9780511526282Google Scholar
  28. G. Talenti: Best constant in Sobolev inequality, Ann. Mat. Pura Appl. (4) 110 (1976) 353–372.https://doi.org/10.1007/BF02418013Google Scholar
  29. L. Tartar: An Introduction to Sobolev Spaces and Interpolation Spaces, Lecture Notes of the Unione Matematica Italiana 3, Springer, Berlin (2007).Google Scholar
  30. A. Wannebo: Hardy inequalities, Proc. Amer. Math. Soc. 109 (1990) 85–95.https://doi.org/10.1090/S0002-9939-1990-1010807-1Google Scholar

F. Prinari, A. C. Zagati. “On the Sharp Makai Inequality.” Journal of Convex Analysis 31 (2024), No. 2, 709–732. https://doi.org/10.68381/jca31034