Abstract
In his "23 Mathematische Probleme" lecture to the Paris International Congress in 1900, David Hilbert wrote "Besides it is an error to believe that rigor in the proof is the enemy of simplicity." In this spirit, we use simple convex analytic methods, relying on an ingenious function due to Simon Fitzpatrick, to provide a concise proof of the maximality of the sum of two maximal monotone operators on reflexive Banach space under standard transversality conditions. Various other surjectivity, convexity and local boundedness results are likewise established.
References
- E. Asplund: A monotone convergence theorem for sequences of nonlinear mappings, Proc. Sympos. Pure Math. 18, Part 1 (1970) 1–9.https://doi.org/10.1090/pspum/018.1/0275240Google Scholar
- E. Asplund: Topics in the theory of convex function, in: Theory and Applications of Monotone Operators (Proc. NATO Advanced Study Inst., Venice, 1968), Edizioni “Oderisi", Gubbio (1969) 1–33.Google Scholar
- A. Auslander, M. Teboulle: Asymptotic Cones and Functions in Optimization and Variational Inequalities, Springer, New York (2003).Google Scholar
- H. H. Bauschke, J. M. Borwein: Maximal monotonicity of dense type, local maximal monotonicity, and monotonicity of the conjugate are all the same for continuous linear operators, Pac. J. Math. 189 (1999) 1–20.https://doi.org/10.2140/pjm.1999.189.1Google Scholar
- H. H. Bauschke, D. A. McLaren, H. S. Sendov: Fitzpatrick functions: Inequalities, examples and remarks on a problem of S. Fitzpatrick, J. Convex Analysis 13 (2006) 499–523.https://doi.org/10.68381/jca13043Google Scholar
- J. M. Borwein: Asplund decompositions of monotone operators, in: Control, Set-Valued Analysis & Applications, CSVAA ’04 (Guadeloupe 2004), in press (2005).Google Scholar
- J. M. Borwein, S. Fitzpatrick: Local boundedness of monotone operators under minimal hypotheses, Bull. Australian Math. Soc. 39 (1988) 339–441.https://doi.org/10.1017/S000497270000335XGoogle Scholar
- J. M. Borwein, S. Fitzpatrick, J. Vanderwerff: Examples of convex functions and classifications of normed spaces, J. Convex Analysis 1 (1994) 61–73.https://doi.org/10.68381/jca01004Google Scholar
- J. M. Borwein, A. S. Lewis: Convex Analysis and Nonlinear Optimization: Theory and Examples, CMS Books in Mathematics 3, Springer, New York (2000).https://doi.org/10.1007/978-1-4757-9859-3_4Google Scholar
- J. M. Borwein, Q. J. Zhu: A survey of subdifferential calculus with applications, Nonlinear Anal., Theory Methods Appl. 38 (1999) 687–773.https://doi.org/10.1016/S0362-546X(98)00142-4Google Scholar
- J. M. Borwein, Q. J. Zhu: Techniques of Variational Analysis: An Introduction, CMS Books in Mathematics 20, Springer, New York (2005).Google Scholar
- R. M. Bot, S.-I. Grad, G. Wanka: Maximal monotonicity for the precomposition with a linear operator, preprint (2005).Google Scholar
- R. S. Burachik, S. Fitzpatrick: On a family of convex functions attached to a subdifferential, J. Nonlinear Convex Anal. 6 (2005) 165–172.Google Scholar
- H. Debrunner, P. Flor: Ein Erweiterungssatz für monotone Mengen, Arch. Math. 15 (1964) 445–447.https://doi.org/10.1007/BF01589229Google Scholar
- M. Fabian, P. Habala, P. Hájek, V. Montesinos, J. Pelan, V. Zizler: Functional Analysis and Infinite-Dimensional Geometry, CMS Books in Mathematics 8, Springer, New York (2001).https://doi.org/10.1007/978-1-4757-3480-5Google Scholar
- 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
- S. Fitzpatrick, R. R. Phelps: Bounded approximants to monotone operators on Banach spaces, Ann. Inst. Henri Poincaré, Anal. Non Linéaire 9 (1992) 573–595.https://doi.org/10.1016/s0294-1449(16)30230-xGoogle Scholar
- S. Fitzpatrick, R. R. Phelps: Some properties of maximal monotone operators on nonreflexive Banach spaces, Set-Valued Anal. 3 (1995) 51–69.https://doi.org/10.1007/BF01033641Google Scholar
- S. Gossez: Opérateurs monotones non linéaires dans les espaces de Banach non réflexifs, J. Math. Anal. Appl. 34 (1971) 371–395.https://doi.org/10.1016/0022-247X(71)90119-3Google Scholar
- S. Gossez: On the range of a coercive maximal monotone operator in a nonreflexive Banach space, Proc. Amer. Math. Soc. 35 (1972) 88–92.https://doi.org/10.1090/S0002-9939-1972-0298492-7Google Scholar
- S. Gossez: On a convexity property of the range of a maximal monotone operators, Proc. Amer. Math. Soc. 55 (1976) 358–360.https://doi.org/10.1090/S0002-9939-1976-0397485-2Google Scholar
- E. Krauss: A representation of arbitrary maximal monotone operators via subgradients of skew-symmetric saddle functions, Nonlinear Anal., Theory Methods Appl. 9 (1985) 1381–1399.https://doi.org/10.1016/0362-546X(85)90097-5Google Scholar
- J.-P. Penot: Is convexity useful for the study of monotonicity?, in: Nonlinear Analysis and Applications, R. P. Agarwal, D. O’Regan (eds.), Kluwer, Dordrecht (2003) 807–822.https://doi.org/10.1007/978-94-010-0035-2_12Google Scholar
- J.-P. Penot: The relevance of convex analysis for the study of monotonicity, Nonlinear Anal., Theory Methods Appl. 58 (2004) 855–871.https://doi.org/10.1016/j.na.2004.05.018Google Scholar
- R. R. Phelps: Lectures on maximal monotone operators, Extr. Math. 12 (1997) 193–230.Google Scholar
- R. R. Phelps: Convex Functions, Monotone Operators and Differentiability, Lecture Notes in Mathematics 1364, Springer, Berlin (1989).https://doi.org/10.1007/978-3-662-21569-2Google Scholar
- S. Reich: The range of sums of accretive and monotone operators, J. Math. Anal. Appl. 68 (1979) 310–317.https://doi.org/10.1016/0022-247X(79)90117-3Google Scholar
- R. T. Rockafellar: Local boundedness of nonlinear monotone operators, Mich. Math. J. 16 (1969) 397–407.https://doi.org/10.1307/mmj/1029000324Google Scholar
- 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
- R. T. Rockafellar: Convex Analysis, Princeton University Press, Princeton (1970).https://doi.org/10.1515/9781400873173Google Scholar
- S. Simons: Minimax and Monotonicity, Lecture Notes in Mathematics 1693, Springer, Berlin (1998).https://doi.org/10.1007/BFb0093633Google Scholar
- S. Simons: Five kinds of maximal monotonicity, Set-Valued Anal. 9 (2001) 391–403.https://doi.org/10.1023/A:1012664003952Google Scholar
- S. Simons: A new version of the Hahn-Banach theorem (2003), available at www.math.ucsb.edu/~simons/preprints/https://doi.org/10.1007/s00013-003-0500-2Google Scholar
- S. Simons: Dualized and scaled Fitzpatrick functions, Proc. Amer. Math. Soc., in press (2005), available at www.math.ucsb.edu/~simons/preprints/https://doi.org/10.1090/S0002-9939-06-08363-8Google Scholar
- S. Simons, C. Zălinescu: A new proof for Rockafellar’s characterization of maximal monotone operators, Proc. Amer. Math. Soc. 132 (2004) 2969–2972.https://doi.org/10.1090/S0002-9939-04-07462-3Google Scholar
- S. Simons, C. Zălinescu: Fenchel duality, Fitzpatrick functions and maximal monotonicity, J. Nonlinear Convex Anal. 6 (2005) 1–22.Google Scholar
- A. Verona, M. E. Verona: Regular maximal monotone operators and the sum rule, J. Convex Analysis 7 (2000) 115–128.https://doi.org/10.68381/jca07006Google Scholar
- C. Zălinescu: A new proof of the maximal monotonicity of the sum using the Fitzpatrick function, in: Variational Analysis and Applications, F. Giannessi, A. Maugeri (eds.), Kluwer, Dordrecht, to appear.Google Scholar
- C. Zălinescu: Convex Analysis in General Vector Spaces, World Scientific, Singapore (2002).https://doi.org/10.1142/5021Google Scholar
- C. Zălinescu: A new convexity property for monotone operators, J. Convex Analysis 13 (2006) 883–887.https://doi.org/10.68381/jca13065Google Scholar
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Published by Heldermann Verlag, 2006. Rights now held by Banach Press LLC.
