The Complexity of Revision, Revised

The purpose of this note is to acknowledge a gap in a previous paper — “The Complexity of Revision”, see [1] — and provide a corrected version of argument. The gap was originally pointed out by Francesco Orilia (personal communication and [4]), and the fix was developed in correspondence with Vann McGee. The main point of the argument given in [1] is to show that the Gupta-Belnap revision-theoretic system S∗ admits of an analogue of the Löwenheim-Skolem theorem for first-order logic (all notation and terminology are defined in [2]). In particular, a crucial step in the argument requires that we show the following: