G4 Prover
    
Result of the test for sequent ~(p/\q) <--> ~p\/ ~q 



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)<--> ~p\/ ~q.
Trying to prove with threshold = 0 1 2 3 4 5
Fail to prove ~ (p/\q) --> ~p\/ ~q (15 msec.)
Trying to prove with threshold = 0
Succeed in proving ~p\/ ~q --> ~ (p/\q) (3 msec.)
pretty:1 =
--------------- Ax         --------------- Ax
bot,q,p --> bot            p,bot,q --> bot
------------------ L0->1   ------------------ L0->1
p,q,p->bot --> bot         p,q,q->bot --> bot
------------------- L/\    ------------------- L/\
p/\q,p->bot --> bot        p/\q,q->bot --> bot
------------------- R~     ------------------- R~
p->bot --> ~ (p/\q)        q->bot --> ~ (p/\q)
------------------- L~def  ------------------- L~def
  ~p --> ~ (p/\q)            ~q --> ~ (p/\q)
  ------------------------------------------ L\/
             ~p\/ ~q --> ~ (p/\q)
yes
fol(g4i)> quit.
yes
Exit from Sequent Calculus Prover...
Total CPU time = 21 msec.
true 


  

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Maintained by  Joseph Vidal-Rosset