With the coefficient matrices of the polynomial matrices replacing the scalar coefficients in the standard Sylvester matrix, common factors exist if and only if this (generalized) Sylvester matrix is singular and the coefficient matrices commute. If the coefficient matrices do not commute, a...

Did adoption of the gold standard exacerbate or diminish macroeconomic volatility? Supporters thought so, critics thought not, and theory offers ambiguous messages. A hard exchange-rate regime such as the gold standard might limit monetary shocks if it ties the hands of policy makers. But any...

Within an incomplete information framework (where the primitives are the individuals'' belief hierarchies) we investigate the intersubjective implications of the assumption that it is common belief that no individual has any false beliefs (a key component of the Truth Axiom). We consider two...

Before condemning data mining one should distinguish between objective and biased data mining. The former is commendable. Even biased data mining is appropriate when used to illustrate and not to test hypotheses. In the context of testing, the problem with biased data mining arises not from the...

The main result of this paper characterizes possibly non-symmetric strategy-proof and efficienct choice functions as Perfectly Competitive. Efficiency is defined as impossibility of improvement by reallocation of commodity among finite sets of agents, and largeness of the economy is captured by...

We generalize the ``No-speculative-trade" theorem for finite unawareness belief structures in Heifetz, Meier, and Schipper (2013) to the infinite case.

We present a non-technical account of ambiguity in strategic games and show how it may be applied to economics and social sciences. Optimistic and pessimistic responses to ambiguity are formally modelled. We show that pessimism has the effect of increasing (decreasing) equilibrium prices under...

In this paper we compare two different approaches to modeling unawareness: the object-based approach of Board and Chung (2007) and the subjective-state-space approach of Heifetz, Meier and Schipper (2006).

This paper investigates the effects of temporal aggregation when the aggregation frequency is variable and possibly stochastic. The results that we report include, as a particular case, the well-known results on fixed-interval aggregation, such as when monthly data is aggregated into quarters. A...