Research activity of
Pierluigi Benevieri

My research activity concerns mainly the following fields :

$\bullet$ Topological degree theory.
$\bullet$ Topological methods in differential delay equations.
$\bullet$ Differential topology in general economic equilibrium theory.


Topological degree theory

The research in this area is in collaboration with Prof. Massimo Furi and Prof. Maria Patrizia Pera.

The most important result obtained is the construction of a concept of oriented degree for nonlinear Fredholm maps of indez zero between differentiable manifolds modeled on Banach spaces.

The starting point of this construction is a (merely algebraic) notion of orientation for linear Fredholm maps between real vector spaces.

This notion allows to define an orientation for nonlinear Fredholm maps of index zero between Banach manifolds and the degree is defined for the so called orientable maps.

This concept of degree is connected with other theories. You can see in particular papers of Elworthy-Tromba and Fitzpatrick-Pejsachowicz-Rabier.



Topological methods in differential delay equations

This topic has been studied during three months in Rutgers University, NJ, USA, with the supervision of Prof. Roger Nussbaum. The research in this area started with some `state dependent time lag' equations. The purpose is the application of topological tools as Fuller index and recent extensions of Fenske.



Differential topology in general economic equilibrium theory.

This is a project in collaboration with Prof. Andrea Battinelli of University of Siena, Dott. Laura Carosi of University of Pisa and Prof. Antonio Villanacci of University of Firenze.

Recent publications

1 P. Benevieri, Recenti sviluppi nella teoria del grado topologico, Boll. UMI, 1-A (8) Suppl. (1998), (fascicolo speciale dedicato alle tesi di dottorato) 81-84 (file PDF).

2 P. Benevieri and M. Furi, A simple notion of orientability for Fredholm maps between Banach manifolds and degree theory, Annales des sciences mathémathiques du Québec, 22 n. 2 (1998), 131-148 (file PDF).

3 P. Benevieri and M. Furi, On the concept of orientability for Fredholm maps between real Banach manifolds, Topol. Methods Nonlinear Anal, 16 (2000), no. 2, 279-306 (file PDF).

4 P.Benevieri, M. Furi and M. P. Pera The Invariance of Domain for C1 Fredholm maps of index zero, Recent trends in nonlinear analysis, Progr. Nonlinear Differential Equations Appl., 40, Birkhäuser, Basel, 2000, 35-39 (file PDF).

5 P.Benevieri Orientation and degree for Fredholm maps of index zero between Banach spaces, Nonlinear analysis and its applications to differential equations (Lisbon, 1998), 201-213, Progr. Nonlinear Differential Equations Appl., 43, Birkhäuser Boston, Boston, MA, 2001 (file PDF).

6 P. Benevieri, M. Furi, Bifurcation results for families of Fredholm maps of index zero between Banach spaces, Nonlinear analysis and its applications (St. John's, NF, 1999). Nonlinear Anal. Forum 6 (2001), no. 1, 35-47 (file PDF).

7 P. Benevieri, M. Furi and M. P. Pera, On the Product Formula for the oriented degree for Fredholm maps of index zero between Banach manifolds, Nonlinear Anal. 48 (2002), no. 6, Ser. A: Theory Methods, 853-867 (file PDF).

8 A. Villanacci, A. Battinelli, P. Benevieri and L. Carosi, Differential Topology and General Equilibrium with Complete and Incomplete Markets, Kluwer Academic Publishers, Dordrecht, 2002.

9 P. Benevieri, M. Furi, M. P. Pera and M. Spadini, About the Sign of Oriented Fredholm Operators between Banach Spaces, Z. Anal. Anwendungen, 22 (2003), 3, 619-654 (file PDF).

10 P. Benevieri, A. Gavioli and M. Villarini, Existence of Periodic Orbits for Vector Fields via Fuller Index and the Averaging Method, preprint.