We use an extensive form, universal type space to provide the following epistemic characterisation of extensive form rationalisability. Say that player i strongly believes event E if i is certain of E conditional on each of her information sets consistent with E. Our main contribution is to show...

In a large family of solution concepts for boundedly rational players - allowing players to be imperfect optimizers, but requiring that better responses are chosen with probabilities at least as high as those of worse responses - most of Thompson's inessential transformations for the strategic...