“…One such game, for example, is ‘DC’ (Mackenzie, 1979), a system that has received much attention as a vehicle for interactive computer systems (e.g. Moore & Hobbs, 1996; Amgoud et al , 2000; Maudet & Moore, 2001; Yuan et al ., 2007a, 2008; Reed & Wells, 2007). The system allows five move types: statement (‘P’, ‘Q’, etc., and their truth functional compounds), withdrawals (e.g.…”