 Temporal logics While infinite game forms were briefly alluded to in  Section 2.10,  infinite play focuses on agency over time. A host of temporal logics for this end have been put forward, including interpreted systems (Fagin, Halpern et al. 1995), epistemic-temporal logic (Parikh &amp; Ramanujam 2003), STIT (Belnap &amp; Perloff 1988; Horty &amp; Belnap 1995), ATL (Alur, Henzinger, &amp; Kupferman 2002; van der Hoek &amp; Wooldridge 2003), and others. Many of these systems combine multiple modalities. Consequentially, their complexity can be very high (undecidable, non-axiomatizable, or even non-arithmetical), as Halpern &amp; Vardi (1986) show in a pioneering study for the case of combining time and knowledge. Surveying this area is beyond the scope of this entry, cf. the entry on  temporal logics.  A unifying view of connections between the various paradigms is presented in van Benthem and Pacuit (2006).