Intuitionistic logic Kreisel–Putnam logic 1.𝐴∨¬𝐴 A∨¬A A∨¬ALaw of excluded middleaxiom▲ Intuitionistic logic 2.¬¬𝐴⊃𝐴 ¬¬A⊃A ¬¬A→ADouble negation eliminationaxiom▲ Intuitionistic logic