Theorem prover for Intuitionistic propositional logic using the G3 sequent calculus of [TroSch:2001] (this calculus is due to Kleene). This calculus requires contraction on the main-formula in the application of left-implies rule to guarantee completeness of the proof-search. This implies that a proof-search procedure must performs some checks to avoid loops. Usually this check amounts to check that the set generated by a left-implies application is new. In G3LLC we adopt a different strategy that only looks at the actual stage of the deduction. LLC stands for Local Loop-Checking.
The language consider formulas based on the propositional constants:
true, false, AND, OR, IMPLIES
NOT H is treated as H IMPLIES false.