I also examine Brouwer's 1927 proof of the negative continuity theorem, which appears to be a weak counterexample reliant on both the creative subject and the concept of choice sequence; I argue that ...

Dimiter Vakarelov, Nelson's Negation on the Base of Weaker Versions of Intuitionistic Negation, Studia Logica: An International Journal for Symbolic Logic, Vol. 80, No. 2/3, Negation in Constructive ...

Quantified Boolean Formulas (QBF) extend classical Boolean logic by incorporating quantifiers over Boolean variables, thereby enabling the expression of problems in the PSPACE complexity class.