 Soundness/Completeness of Tableaux. Felscher (1985) showed that there is a tableau proof for \(\varphi\) if and only if there is a winning P strategy in the intuitionistic dialogical game for \(\varphi\). This being the first correct and complete proof, it is very influential in some dialogical traditions, despite the fact that Felscher’s rules do not guarantee finiteness of plays.