Finite validity of formulas of a special form. (English. Russian original) Zbl 0209.30401
Sov. Math., Dokl. 8, 648-650 (1967); translation from Dokl. Akad. Nauk SSSR 174, 302-304 (1967).
MSC:
03B20 | Subsystems of classical logic (including intuitionistic logic) |