G4 Prover

Result of the test for sequent p->q <--> ~q-> ~p

G4 Prover: a Prolog Prover for Roy Dyckhoff's Sequent Calculus G4 This prover is a fork made by Joseph Vidal-Rosset (joseph.vidal-rosset@gmail.com), from seqprover.pl, the sequent prover for CL-X, written by Naoyuki Tamura (tamura@kobe-u.ac.jp). Type "help." if you need some help. fol(g4i)> fol(g4i). yes fol(g4i)> output(pretty). yes fol(g4i)> p->q<--> ~q-> ~p. Trying to prove with threshold = 0 Succeed in proving p->q --> ~q-> ~p (1 msec.) pretty:1 = --------------- Ax bot,q,p --> bot ------------------ L0->1 q,q->bot,p --> bot --------------------- L0->1 p,q->bot,p->q --> bot --------------------- R~ q->bot,p->q --> ~p ------------------ L~def ~q,p->q --> ~p ---------------- R-> p->q --> ~q-> ~p Trying to prove with threshold = 0 1 2 3 4 5 Fail to prove ~q-> ~p --> p->q (13 msec.) yes fol(g4i)> quit. yes Exit from Sequent Calculus Prover... Total CPU time = 18 msec. true

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Maintained by Joseph Vidal-Rosset