The present paper considers a class of general equilibrium economics when the primitive uncertainty model features uncertainty about continuous-time volatility. This requires a set of mutually singular priors, which do not share the same null sets. For this setting we introduce an appropriate...

This paper reconsiders the theory of existence of efficient allocations and equilibria when consumption sets are unbounded below under the assumption that agents have incomplete preferences. Our model is motivated by an example in the theory of assets with short-selling where there is risk and...

The theory of existence of equilibrium with short-selling is reconsidered under risk and ambiguity modelled by risk averse variational preferences. No-arbitrage conditions are given in terms of risk adjusted priors. A sufficient condition for existence of efficient allocations is the overlapping...

The theory of existence of equilibrium with short-selling is reconsidered under risk and ambiguity modelled by risk averse variational preferences. A sufficient condition for existence of efficient allocations is that the relative interiors of the risk adjusted sets of expectations overlap. This...

I extend the classical general equilibrium treatment of uncertainty about exogenous states of nature to uncertainty about prices. Traders do not know the prices at which markets will clear but have expectations over possible prices. They trade price-contingent securities (derivatives) to insure...

We consider fundamental questions of arbitrage pricing arising when the uncertainty model incorporates volatility uncertainty. With a standard probabilistic model, essential equivalence between the absence of arbitrage and the existence of an equivalent martingale measure is a folk theorem, see...

We consider fundamental questions of arbitrage pricing arising when the uncertainty model is given by a set of possible mutually singular probability measures. With a single probability model, essential equivalence between the absence of arbitrage and the existence of an equivalent martingale...

We investigate risk averse agents who manage risk by trading financial securities in a market that we call a risk market. We assume this market is perfectly competitive and complete. When risk aversion is expressed using risk measures, the (bundle of) prices for financial securities turns out to...

To analyze the economic significance of pricing errors of stock index options, a system of linear inequalities is developed which completely characterizes all risk arbitrage opportunities which arise if a well-behaved pricing kernel does not exist. The Stochastic Arbitrage system can account for...

In this paper, we analyze equilibrium in incomplete markets of random endowments by adopting utility indifference pricing and utility-based pricing. Addressing model uncertainty, we also consider agents who adopt max/min expected utility and a risk management policy. Using this framework, we...