Topological aspects of suitable theories

Abstract

Roughly speaking a suitable theory is a theory T together with its formal provability predicate Prv (.). A pseudo-topological space is a boolean algebra B which carries a derivative operation d and its associated closure operation c. Thus we can pretend that B is a topological space. We show that the Lindenbaum algebra B(T) of a suitable theory becomes, in a natural way, a pseudotopological space, and hence we can translate properties of T into topological language, as properties of B(T). We do this translation for several properties of T, including (1) satisfying Gödel's first theorem, (2) satisfying Löb's theorem and (3) asserting one's own inconsistency. These correspond to the topological properties (1) having an isolated point, (2) being scattered, (3) being discrete.