Abstract
The standard state-spaces of asymmetric information preclude non-trivial forms of unawareness (Modica and Rustichini (Theory Decision 37 (1994) 107-124); Dekel, Lipman and Rustichini (Econometrica 66 (1998) 159-173)). We introduce a generalized state-space model that allows for non-trivial unawareness among several individuals, and which satisfies strong properties of knowledge as well as all the desiderata on unawareness proposed this far in the literature. © 2005 Elsevier Inc. All rights reserved.