Working papers
IGIER fellows and affiliates publish books and articles in academic journals. Their current research projects are featured in the Working Paper series.
We provide both an axiomatic and a neuropsychological characterization of the dependence of choice probabilities on time in the softmax (or Multinomial Logit Process) form (see below picture) MLP is the most widely used model of preference discovery in all fields of decision making, from Quantal Response Equilibrium to Discrete Choice Analysis, from Psychophysics and Neuroscience to Combinatorial Optimization. Our axiomatic characterization of softmax permits to empirically test its descriptive validity and to better understand its conceptual underpinnings as a theory of agents'rationality. Our neuropsychological foundation provides a computational model that may explain softmax emergence in human behavior and that naturally extends to multialternative choice the classical Diffusion Model paradigm of binary choice. These complementary approaches provide a complete perspective on softmaximization as a model of preference discovery, both in terms of internal (neuropsychological) causes and external (behavioral) effects.
What explains the formation and decay of clusters of creativity? We match data on notable
individuals born in Europe between the XIth and the XIXth century with historical city data.
The production and attraction of creative talent is associated with city institutions that protected economic and political freedoms and promoted local autonomy. Instead, indicators of local economic conditions such as city size and real wages, do not predict creative clusters. We also show that famous creatives are spatially concentrated and clustered across disciplines, that their spatial mobility has remained stable over the centuries, and that creative clusters are persistent but less than population.
uential findings that, we argue, face serious identification problems. Thus, while banks with low capital can be an important source of aggregate inefficiency in the long run, their contribution to the severity of the great recession via capital misallocation was modest.
We study monotone, continuous, and quasiconcave functionals defifined over an M-space. We show that if g is also Clarke-Rockafellar differentiable at (see below picture) , then the closure of Greenberg- Pierskalla differentials at x coincides with the closed cone generated by the Clarke-Rockafellar differentials at x. Under the same assumptions, we show that the set of normalized Greenberg-Pierskalla differentials at x coincides with the closure of the set of normalized Clarke-Rockafellar differentials at x. As a corollary, we obtain a differential characterization of quasiconcavity a la Arrow and Enthoven (1961) for Clarke-Rockafellar differentiable functions.
Does welfare improve when firms are better informed about the state of the economy and can better coordinate their decisions? We address this question in an elementary business-cycle model that highlights how the dispersion of information can be the source of both nominal and real rigidity. Within this context we develop a taxonomy for how the social value of information depends on the two rigidities, on the sources of the business cycle, and on the conduct of monetary policy.
a Hahn-Banach Theorem for modules of this kind;
a topology on the f-algebra that has the special feature of coinciding with the norm topology when the algebra is a Banach algebra and with the strong order topology of Filipovic, Kupper, and Vogelpoth (2009), when the algebra of all random variables on a probability space is considered.
As a leading example, we study in some detail the duality of conditional Lp-spaces.
Maccheroni, Marinacci, and Rustichini [17], in an Anscombe-Aumann framework, axiomatically characterize preferences that are represented by the variational utility functional where u is a utility function on outcomes and c is an index of uncertainty aversion. In this paper, for a given variational preference, we study the class of functions c that represent V. Inter alia, we show that this set is fully characterized by a minimal and a maximal element, c* and d*. The function c*, also identified by Maccheroni, Marinacci, and Rustichini [17], fully characterizes the decision maker's attitude toward uncertainty, while the novel function d* characterizes the uncertainty perceived by the decision maker.