We develop a theory of optimal stopping problems under ambiguity in continuous time. Using results from (backward) stochastic calculus, we characterize the value function as the smallest (nonlinear) supermartingale dominating the payoff process. For Markovian models, we derive an adjusted...

The influence of heterogeneous time preferences on the term structure is investigated. Motivated by the Preferred Habitat Theory of Modigliani and Sutch, a model for intertemporal preferences accounting for preferred habitats is proposed. In a heterogeneous world, preferred habitats can explain...

We develop the fundamental theorem of asset pricing in a probability-free infinite-dimensional setup. We replace the usual assumption of a prior probability by a certain continuity property in the state variable. Probabilities enter then endogenously as full support martingale measures (instead...

The effect of incomplete information on the term structure of interest rates is examined in the framework of a pure exchange economy under uncertainty. When the growth rate of the aggregate endowment is known, the term structure is flat and deterministic. When agents do not observe the...

In infinite horizon economies only local equivalence of beliefs is needed to ensure the existence of an Arrow-Debreu equilibrium. In fact, agents can even disagree completely in the long run in the sense that asymptotically, their beliefs are singular. -- Heterogeneous expectations ;...