We extend the Fundamental Theorem of Finance and the Pricing Rule Representation Theorem of Cox and Ross (see Ross [35] and [37] and Cox and Ross [9]) to the case in which market frictions are aken into account but the Put-Call Parity is still assumed to hold. In turn, we obtain a representation...

Starting with the seminal paper of Gilboa and Schmeidler (1989) an analogy between the maxmin approach of Decision Theory under Ambiguity and the minimax approach of Robust Statistics -- e.g. Huber and Strassen (1973) -- has been hinted at. The present paper formally clarifies this relation by...

We propose to bring together two conceptually complementary ideas: (1) selfconfi?rming equilibrium (SCE): at a rest point of learning dynamics in a game played recurrently, agents best respond to confi?rmed beliefs, i.e. beliefs consistent with the evidence they accumulate, and (2) ambiguity...

We provide a bridge between Bewley preferences [2] and Uncertainty averse preferences [4]. In doing this, we generalize the ?ndings of Gilboa, Maccheroni, Marinacci, and Schmeidler [11]. To exemplify this new framework, we then study a class of preferences that we call Constrained Multiplier...

In a decision problem under uncertainty, a decision maker considers a set of alternative actions whose consequences depend on uncertain factors outside his control. Following Luce and Raiffa (1957), we adopt a natural representation of such situation that takes as primitives a set of conceivable...

Given a functional defi?ned on a nonempty subset of an Archimedean Riesz space with unit, necessary and sufficient conditions are obtained for the existence of a (convex or concave) niveloid that extends the functional to the entire space. In the language of mathematical fi?nance, this problem...

We consider decision makers that know that payo¤ relevant observations are generated by a process that belongs to a given class M, as postulated in Wald [33]. We incorporate this Waldean piece of objective information within an otherwise subjective setting a la Savage [30] and show that this...

We give a general integral representation theorem (Theorem 6) for nonadditive functionals de?ned on an Archimedean Riesz space X with order unit. Additivity is replaced by a weak form of modularity, or equivalently dual comonotonic additivity, and integrals are Choquet integrals. Those integrals...

Our recent research emphasizes the importance of information feedback in situations of recurrent decisions and strategic interaction, showing how it affects the uncertainty that underlies selfconfi?rming equilibrium. Here we discuss in detail the properties of such a key feature of recurrent...

Many violations of the Independence axiom of Expected Utility can be traced to subjects' attraction to risk-free prospects. Negative Certainty Independence, the key axiom in this paper, formalizes this tendency. Our main result is a utility representation of all preferences over monetary...