The goal of this article is to provide characterizations of monotonicity and maximality via new properties of the Fitzpatrick function associated with a multi-valued operator. Several calculus rules for maximal monotone operators in non-reflexive Banach space settings are presented. In particular positive answers to Rockafellar's conjecture on the maximality of the sum and the chain rule in the linear case are given.

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

Mircea D. Voisei

Dept. of Mathematics, Towson University, 7800 York Road, Towson, MD 21252, U.S.A.

mvoisei@utpa.edu
  1. E. Asplund: A monotone convergence theorem for sequences of nonlinear mappings, Nonlin. Functional Analysis, Proc. Sympos. Pure Math. 18, Part 1 (1970) 1–9.https://doi.org/10.1090/pspum/018.1/0275240Google Scholar
  2. H. Attouch: On the maximality of the sum of two maximal monotone operators, Nonlinear Anal., Theory Methods Appl. 2 (1981) 143–147.https://doi.org/10.1016/0362-546X(81)90039-0Google Scholar
  3. H. Attouch, H. Riahi, M. Théra: Somme ponctuelle d’opérateurs maximaux monotones, Serdica Math. J. 22 (1996) 165–190 (in French).Google Scholar
  4. L. J. Chu: On the sum of monotone operators, Mich. Math. J. 43 (1996) 273–289.https://doi.org/10.1307/mmj/1029005463Google Scholar
  5. S. Fitzpatrick: Representing monotone operators by convex functions, in: Functional Analysis and Optimization, Workshop / Miniconference (Canberra, 1988), Proc. Cent. Math. Anal. Aust. Natl. Univ. 20, Australian National University, Canberra (1988) 59–65.Google Scholar
  6. J. P. Gossez: On the subdifferential of a saddle function, J. Funct. Anal. 11 (1972) 220–230.https://doi.org/10.1016/0022-1236(72)90092-4Google Scholar
  7. J. P. Gossez: Opérateurs monotones non linéaires dans les espaces de Banach non réflexifs, J. Math. Anal. Appl. 34 (1971) 371–395 (in French).https://doi.org/10.1016/0022-247X(71)90119-3Google Scholar
  8. E. Krauss, D. Tiba: Regularization of saddle functions and the Yosida approximation of monotone operators, An. Ştiinţ. Univ. Al. I. Cuza Iaşi, N. Ser., Secţ. Ia 31 (1985) 215–220.Google Scholar
  9. E. Krauss: Maximal monotone operators and saddle functions. I., Z. Anal. Anwend. 5 (1986) 333–346.https://doi.org/10.4171/zaa/202Google Scholar
  10. J. E. Martinez-Legaz, M. Théra: A convex representation of maximal monotone operators, J. Nonlinear Convex Anal. 2(2) (2001) 243–247.Google Scholar
  11. J. P. Penot: The relevance of convex analysis for the study of monotonicity, Nonlinear Anal., Theory Methods Appl. 58A(7–8) (2004) 855–871.https://doi.org/10.1016/j.na.2004.05.018Google Scholar
  12. J. P. Penot: Natural closures, natural compositions and natural sums of monotone operators, preprint (2006).Google Scholar
  13. R. R. Phelps, S. Simons: Unbounded linear monotone operators on nonreflexive Banach spaces, J. Convex Analysis 5(2) (1998) 303–328.https://doi.org/10.68381/jca05-21Google Scholar
  14. R. T. Rockafellar: On the maximal monotonicity of subdifferential mappings, Pac. J. Math. 33 (1970) 209–216.https://doi.org/10.2140/pjm.1970.33.209Google Scholar
  15. R. T. Rockafellar: On the maximality of sums of nonlinear monotone operators, Trans. Amer. Math. Soc. 149 (1970) 75–88.https://doi.org/10.1090/S0002-9947-1970-0282272-5Google Scholar
  16. R. T. Rockafellar: Monotone operators associated with saddle-functions and minimax problems, Nonlin. Functional Analysis, Proc. Sympos. Pure Math. 18, Part 1 (1970) 1–9.https://doi.org/10.1090/pspum/018.1/0285942Google Scholar
  17. S. Simons: Sum theorems for monotone operators and convex functions, Trans. Amer. Math. Soc. 350(7) (1998) 2953–2972.https://doi.org/10.1090/S0002-9947-98-02045-5Google Scholar
  18. S. Simons: Pairs of monotone operators, Trans. Amer. Math. Soc. 350(7) (1998) 2973–2980.https://doi.org/10.1090/S0002-9947-98-02104-7Google Scholar
  19. S. Simons: Minimax and Monotonicity, Lecture Notes in Mathematics 1693, Springer, Berlin (1998).https://doi.org/10.1007/BFb0093633Google Scholar
  20. S. Simons: Maximal monotone multifunctions of Brondsted-Rockafellar type, Set-Valued Anal. 7(3) (1999) 255–294.https://doi.org/10.1023/A:1008779514159Google Scholar
  21. S. Simons: The Fitzpatrick function and nonreflexive spaces, J. Convex Analysis 13 (2006) 861–881.https://doi.org/10.68381/jca13064Google Scholar
  22. A. Verona, M. E. Verona: Regular maximal monotone operators and the sum theorem, J. Convex Analysis 7(1) (2000) 115–128.https://doi.org/10.68381/jca07006Google Scholar
  23. A. Verona, M. E. Verona: Remarks on subgradients and ε-subgradients, Set-Valued Anal. 1(3) (1993) 261–272.https://doi.org/10.1007/BF01027637Google Scholar
  24. M. D. Voisei: A maximality theorem for the sum of maximal monotone operators in non-reflexive Banach Spaces, Math. Sci. Res. J. 10(2) (2006) 36–41.Google Scholar
  25. M. D. Voisei: The sum theorem for linear maximal monotone operators, Math. Sci. Res. J. 10(4) (2006) 83–85.Google Scholar
  26. C. Zălinescu: Convex Analysis in General Vector Spaces, World Scientific, Singapore (2002).https://doi.org/10.1142/5021Google Scholar
  27. C. Zălinescu: A new proof of the maximal monotonicity of the sum using the Fitzpatrick function, in: Variational Analysis and Applications, F. Giannessi et al. (ed.), Nonconvex Optimization and its Applications 79, Springer, New York (2005) 1159–1172.https://doi.org/10.1007/0-387-24276-7_66Google Scholar

M. D. Voisei. “Calculus Rules for Maximal Monotone Operators in General Banach Spaces.” Journal of Convex Analysis 15 (2008), No. 1, 73–85. https://doi.org/10.68381/jca15006