This article characterizes conjugates and subdifferentials of convex integral functionals over the linear space of stochastic processes of essentially bounded variation (BV) when the space is identified with the Banach dual of the space of regular processes. Our proofs are based on new results on the interchange of integration and minimization of integral functionals over BV processes. Under mild conditions, the domain of the conjugate is shown to be contained in the space of semimartingales which leads to several applications in the duality theory in stochastic control and mathematical finance.

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

Ari-Pekka Perkkiö

Dept. of Mathematics, Ludwig Maximilians Universität, Theresienstr. 39, 80333 München, Germany

perkkioe@math.tu-berlin.de
  1. J.-M. Bismut: Conjugate convex functions in optimal stochastic control, J. Math. Anal. Appl. 44 (1973) 384–404.https://doi.org/10.1016/0022-247X(73)90066-8Google Scholar
  2. J.-M. Bismut: Régularité et continuité des processus, Z. Wahrsch. Verw. Gebiete 44(3) (1978) 261–268.https://doi.org/10.1007/BF00534214Google Scholar
  3. G. Bouchitté, M. Valadier: Integral representation of convex functionals on a space of measures, J. Funct. Anal. 80(2) (1988) 398–420.https://doi.org/10.1016/0022-1236(88)90009-2Google Scholar
  4. C. Dellacherie, P.-A. Meyer: Probabilities and Potential B, North-Holland Mathematics Studies 72, North-Holland, Amsterdam (1982).Google Scholar
  5. G. B. Folland: Real Analysis (2nd ed.), Pure and Applied Mathematics, Wiley, New York (1999).Google Scholar
  6. S. W. He, J. G. Wang, J. A. Yan: Semimartingale theory and stochastic calculus, Kexue Chubanshe (Science Press) Beijing and CRC Press, Boca Raton (1992).Google Scholar
  7. M. Kiiski, A.-P. Perkkiö: Optional and predictable projections of normal integrands and convex-valued processes, Set-Valued Var. Analysis 25(2) (2017) 313–332.https://doi.org/10.1007/s11228-016-0381-8Google Scholar
  8. T. Pennanen, A.-P. Perkkiö: Duality in convex problems of Bolza over functions of bounded variation, SIAM J. Control Optimization 52(3) (2014) 1481–1498.https://doi.org/10.1137/130917612Google Scholar
  9. T. Pennanen, A.-P. Perkkiö: Integral functionals of regular processes, Arxiv (2016).Google Scholar
  10. A.-P. Perkkiö: Continuous essential selections and integral functionals, Set-Valued Var. Analysis 22(1) (2014) 45–58.https://doi.org/10.1007/s11228-013-0249-0Google Scholar
  11. A.-P. Perkkiö: Conjugates of integral functionals on continuous functions, Arxiv (2017).Google Scholar
  12. W. R. Pestman: Measurability of linear operators in the Skorokhod topology, Bull. Belg. Math. Soc. Simon Stevin 2(4) (1995) 381–388.https://doi.org/10.36045/bbms/1103408695Google Scholar
  13. R. T. Rockafellar: Level sets and continuity of conjugate convex functions, Trans. Amer. Math. Soc. 123 (1966) 46–63.https://doi.org/10.1090/S0002-9947-1966-0192318-XGoogle Scholar
  14. R. T. Rockafellar: Integrals which are convex functionals, Pacific J. Math. 24 (1968) 525–539.https://doi.org/10.2140/pjm.1968.24.525Google Scholar
  15. R. T. Rockafellar: Integrals which are convex functionals II, Pacific J. Math. 39 (1971) 439–469.https://doi.org/10.2140/pjm.1971.39.439Google Scholar
  16. R. T. Rockafellar: Conjugate Duality and Optimization, Society for Industrial and Applied Mathematics, Philadelphia (1974).https://doi.org/10.1137/1.9781611970524Google Scholar
  17. R. T. Rockafellar: Integral Functionals, Normal Integrands and Measurable Selections, in: Nonlinear Operators and the Calculus of Variations (Summer School, Univ. Libre Bruxelles, Brussels 1975), Lecture Notes Math. 543, Springer, Berlin (1976) 157–207.https://doi.org/10.1007/BFb0079944Google Scholar
  18. R. T. Rockafellar, R. J.-B. Wets: Variational Analysis, Grundlehren der Math. Wissenschaften 317, Springer, Berlin (1998).https://doi.org/10.1007/978-3-642-02431-3Google Scholar
  19. M. Valadier: Convex integrands on Souslin locally convex spaces, Pacific J. Math. 59(1) (1975) 267–276.https://doi.org/10.2140/pjm.1975.59.267Google Scholar

T. Pennanen, A.-P. Perkkiö. “Convex Integral Functionals of Processes of Bounded Variation.” Journal of Convex Analysis 25 (2018), No. 1, 161–179. https://doi.org/10.68381/jca25010