An
appropriate (interim) notion of the core for an economy with incomplete
information depends on the amount of information that coalitions can share.
The coarse and fine core, as originally defined by Wilson (1978), correspond
to two polar cases, involving no information sharing and arbitrary information
sharing, respectively. We propose a new core notion, the credible
core, which incorporates incentive compatibility constraints, and is based
on the idea that a coalition can coordinate its potential objection to
a status-quo over an event that can be credibly inferred from the nature
of the objection being contemplated.