Given an extensive form G, the paper associates with every choice an atomic sentence and with every information set a set of well-formed formulas (wffs) of propositional calculus. The set of such wffs is denoted by ¦)(G). Using the so-called topological semantics for propositional calculus (which differs from the standard one based on truth tables), the paper shows that the extensive form yields a topological model of ¦)(G), that is, every wff in ¦)(G), is ‘true in G’. It also shows that, within the standard truth-table semantics for propositional calculus, there is a one-to-one and onto correspondence between the set of plays of G and the set of valuations that satisfy all the wffs in ¦)(G).
