  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.
