Skip to main content

Advertisement

Log in

Convex analysis and financial equilibrium

  • Full Length Paper
  • Series B
  • Published:
Mathematical Programming Submit manuscript

Abstract

Convexity has long had an important role in economic theory, but some recent developments have featured it all the more in problems of equilibrium. Here the tools of convex analysis are applied to a basic model of incomplete financial markets in which assets are traded and money can be lent or borrowed between the present and future. The existence of an equilibrium is established with techniques that include bounds derived from the duals to problems of utility maximization. Composite variational inequalities furnish the modeling platform. Models with and without short-selling are handled, moreover in the absence of any requirement that agents must initially have a positive amount of every asset, as is typical in equilibrium work in economics.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Notes

  1. Even with borrowing and lending, however, the portfolios may fall short of being able to produce every pattern of payments in the future states, and in that sense the market would be incomplete. In the version of the Arrow-Debreu model with financial-like markets in “contingent” goods, incompletness can block the existence of equilibrium.

  2. For related model with explicit consumption, see our paper [10], which likewise works with variational inequalities.

  3. Differentiability could be dropped, with gradients replaced by subgradients, but for that we would need to work in Sect. 3 with a more complicated type of variational inequality, as we did in [10]. Upper semicontinuity corresponds to the upper level sets of \(u_i\) being closed, as is usual in preference theory.

References

  1. Arrow, K.J.: Le rôle des valeurs boursières pour la répartition la meilleure des risques. Econométrie Colloques Internationaux du Centre National de la Recherche Scientifique 40, : 41–47; English translation: The role of securities in the optimal allocation of risk-bearing. Rev. Econ. Studies 31(1964), 91–96 (1953)

    Google Scholar 

  2. Arrow, K.J., Debreu, G.: Existence of an equilibrium for a competitive economy. Econometrica 22, 265–290 (1954)

    Article  MATH  MathSciNet  Google Scholar 

  3. Debreu, G.: Theory of Value. Wiley, London (1959)

    MATH  Google Scholar 

  4. Debreu, G.: Economies with a finite set of equilibria. Econometrica 38, 387–392 (1970)

    Article  MATH  MathSciNet  Google Scholar 

  5. Dontchev, A.D., Rockafellar, R.T.: Implicit Functions and Solution Mappings: A View From Variational Analysis. Monographs in Math, Springer, Berlin (2009)

  6. Dontchev, A.D., Rockafellar, R.T.: Parametric stability of solutions in models of economic equilibrium. Convex Anal. 19, 975–993 (2012)

    MATH  MathSciNet  Google Scholar 

  7. Geanakoplos, J.: An introduction to general equilibria with incomplete markets. J. Math. Econ. 19, 1–38 (1990)

    Article  MATH  MathSciNet  Google Scholar 

  8. Hens, T.: Incomplete markets. Chapter 5. In: Kirman, A. (ed.) Elements of General Equilibrium Theory, Festschrift in Honor of Gérard Debreu, Blackwell Publishers (1998)

  9. Jofre, A., Rockafellar, R.T., Wets, R.J.-B.: A variational inequality model for determining an economic equilibrium of classical or extended type. In: Giannessi, F., Maugeri, A., (eds.) Variational Analysis and Applications pp. 553–578. Springer, Berlin (2005)

  10. Jofre, A., Rockafellar, R.T., Wets, R.J-B: General economic equilibrium with financial markets and retainability. (Downloadable from www.math.washington.edu/~rtr/mypage.html)

  11. Jofre, A., Rockafellar, R.T., Wets, R. J-B: The robust stability of every equilibrium in economic models of exchange even under relaxed standard conditions. (Downloadable from www.math.washington.edu/~rtr/mypage.html)

  12. Jofre, A., Rockafellar, R.T., Wets, R.J.-B.: Variational inequalities and economic equilibrium. Math. Oper. Res. 32, 32–50 (2007)

    Article  MATH  MathSciNet  Google Scholar 

  13. Magill, M., Shafer, W.; Incomplete markets. In: Hildenbrand, W., Sonnenschein, H., (eds.) Handbook of Mathematical Economics, vol. IV. Elsevier Science Publishers (1991)

  14. Radner, R.: The existence of equilibrium of plans, prices and price expectations. Econometrica 40, 289–303 (1972)

    Article  MATH  MathSciNet  Google Scholar 

  15. Rockafellar, R.T., Wets, R.J-B: Variational Analysis, Grundlehren der Mathematischen Wissenschaften 317, Springer, Berlin (1997)

  16. Rockafellar, R.T.: Convex Analysis. Princeton University Press, Princeton (1970)

    MATH  Google Scholar 

  17. Rockafellar, R.T., Uryasev, S., Zabarankin, M.: Equilibrium with investors using a diversity of deviation measures. J. Banking Financ. 31, 3251–3268 (2007)

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to A. Jofré.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Jofré, A., Rockafellar, R.T. & Wets, R.JB. Convex analysis and financial equilibrium. Math. Program. 148, 223–239 (2014). https://doi.org/10.1007/s10107-014-0747-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10107-014-0747-3

Keywords

Mathematics Subject Classification

Navigation