# An interim core for normal form games and exchange economies with incomplete information: a correction

## TL;DR

This paper introduces a new solution concept for the interim core in normal form games and exchange economies with incomplete information, bridging existing concepts and allowing for more flexible negotiations based on future information.

## Contribution

It develops an interim core concept that lies between Wilson's coarse core and Yannelis's private core, incorporating postponed measurability and conditional negotiations.

## Key findings

- The new solution concept allows for negotiations based on future information.
- It differs from Wilson's and Yannelis's cores by postponing strategy measurability and enabling conditional negotiations.
- Examples illustrate the strengthened interim aspect of the game.

## Abstract

We consider the interim core of normal form cooperative games and exchange economies with incomplete information based on the partition model. We develop a solution concept that we can situate roughly between Wilson's coarse core and Yannelis's private core. We investigate the interim negotiation of contracts and address the two situations of contract delivery: interim and ex post. Our solution differs from Wilson's concept because the measurability of strategies in our solution is postponed until the consumption date (assumed with respect to the information that will be known by the players at the consumption date). For interim consumption, our concept differs from Yannelis's private core because players can negotiate conditional on proper common knowledge events in our solution, which strengthens the interim aspect of the game, as we will illustrate with examples.