My primary research interest is in microeconomic theory, with an emphasis on game theory and decision theory. I have worked on existence of equilibrium in games with payoffs that lack the usual continuity properties, as well as games with incomplete information with neither an *a priori* order structure nor convexity assumptions on strategy spaces or payoff functions. That work has resulted in several working papers, including a contribution to the fixed point theory of decomposable sets in non-linear analysis. More recently, I have been studying learning and belief formation in an environment in which little information is available to the economic agent and surprises are frequent. I have also been continuously involved in the organization of conferences, workshops, seminars, and minicourses for the Australian National University, many of them multidisciplinary.

### Working papers

**On the existence of equilibrium in Bayesian games without complementarities [pdf]**

(with Rabee Tourky)

This paper presents new results on the existence of Bayesian equilibria in pure strategies of a specified functional form. These results broaden the scope of methods developed by Reny (2011) well beyond monotone pure strategies. Applications include natural models of first-price and all-pay auctions not covered by previous existence results. To illustrate the scope of our results, we present two applications to auctions: (i) a first-price auction in which bidders’ payoffs have a very general interdependence structure; and (ii) an all-pay auction with non-monotone equilibrium.

**Keywords: **Bayesian games, monotone strategies, pure-strategy equilibrium, auctions

**A fixed point theorem for closed-graphed decomposable-valued correspondences [pdf]**

(with Rabee Tourky)

Extending the fixed-point theorem of Cellina–Fryszkowski [1, 7], which is for functions on decomposable sets, to decomposable-set-valued correspondences has been an unresolved challenge since the early attempt of Cellina, Colombo, and Fonda [2]. Motivated by the fixed point problem of Reny [12] arising in Bayesian games, this paper proves such a theorem.

**Keywords:** fixed point, decomposable set

### Publications

- Grant, S., Meneghel, I., and Tourky, R. (2022). “Learning under unawareness.”
*Economic Theory*, forthcoming. - Grant, S., Kline, J., Meneghel, I., Quiggin, J., and Tourky, R. (2016). “A theory of robust experiments for choice under uncertainty.”
*Journal of Economic Theory*, 165, pp. 124-151. - Grant, S., Meneghel, I., and Tourky, R. (2016). “Savage games.”
*Theoretical Economics*, 1 (2), pp. 641-682. - Barelli, P. and Meneghel, I. (2013). “A note on the equilibrium existence problem in discontinuous games.”
*Econometrica*, 81 (2), pp. 813-824.