Hi Geoff, go and have some cold beer while I am trying to solve this very hard problem! % remaining time: 3000 next slice time: 185 dis-1002_3_bs=off:bsr=unit_only:gsp=input_only:gs=on:lcm=reverse:nwc=3:ptb=off:ssec=off:sac=on:sgo=on:sio=off:spo=on:swb=on:sp=occurrence:urr=on:updr=off_168 on FNE045 Refutation found. Thanks to Tanya! % SZS status Theorem for FNE045 % SZS output start Proof for FNE045 64. $false (2:0) [unit resulting resolution 7,8,34,6] 6. ~a_truth(implies(X0,X1)) | a_truth(X1) | ~a_truth(X0) (0:8) [cnf transformation 5] 5. ! [X0,X1] : (~a_truth(X0) | a_truth(X1) | ~a_truth(implies(X0,X1))) & ! [X2,X3] : a_truth(implies(X2,implies(X3,X2))) & ~a_truth(implies(sK0,sK0)) & ! [X5,X6] : a_truth(implies(implies(not(X5),not(X6)),implies(X6,X5))) & ! [X7,X8,X9] : a_truth(implies(implies(X7,implies(X8,X9)),implies(implies(X7,X8),implies(X7,X9))))[skolemisation 4] 4. ! [X0,X1] : (~a_truth(X0) | a_truth(X1) | ~a_truth(implies(X0,X1))) & ! [X2,X3] : a_truth(implies(X2,implies(X3,X2))) & ? [X4] : ~a_truth(implies(X4,X4)) & ! [X5,X6] : a_truth(implies(implies(not(X5),not(X6)),implies(X6,X5))) & ! [X7,X8,X9] : a_truth(implies(implies(X7,implies(X8,X9)),implies(implies(X7,X8),implies(X7,X9))))[flattening 3] 3. ~~(! [X0,X1] : (~a_truth(X0) | a_truth(X1) | ~a_truth(implies(X0,X1))) & ! [X2,X3] : a_truth(implies(X2,implies(X3,X2))) & ? [X4] : ~a_truth(implies(X4,X4)) & ! [X5,X6] : a_truth(implies(implies(not(X5),not(X6)),implies(X6,X5))) & ! [X7,X8,X9] : a_truth(implies(implies(X7,implies(X8,X9)),implies(implies(X7,X8),implies(X7,X9)))))[rectify 2] 2. ~~(! [X0,X1] : (~a_truth(X0) | a_truth(X1) | ~a_truth(implies(X0,X1))) & ! [X0,X1] : a_truth(implies(X0,implies(X1,X0))) & ? [X2] : ~a_truth(implies(X2,X2)) & ! [X0,X1] : a_truth(implies(implies(not(X0),not(X1)),implies(X1,X0))) & ! [X0,X1,X3] : a_truth(implies(implies(X0,implies(X1,X3)),implies(implies(X0,X1),implies(X0,X3)))))[negated conjecture 1] 1. ~(! [X0,X1] : (~a_truth(X0) | a_truth(X1) | ~a_truth(implies(X0,X1))) & ! [X0,X1] : a_truth(implies(X0,implies(X1,X0))) & ? [X2] : ~a_truth(implies(X2,X2)) & ! [X0,X1] : a_truth(implies(implies(not(X0),not(X1)),implies(X1,X0))) & ! [X0,X1,X3] : a_truth(implies(implies(X0,implies(X1,X3)),implies(implies(X0,X1),implies(X0,X3)))))[input] 34. a_truth(implies(implies(X0,X1),implies(X0,X0))) (1:8) [unit resulting resolution 7,10,6] 10. a_truth(implies(implies(X7,implies(X8,X9)),implies(implies(X7,X8),implies(X7,X9)))) (0:14) [cnf transformation 5] 8. ~a_truth(implies(sK0,sK0)) (0:4) [cnf transformation 5] 7. a_truth(implies(X2,implies(X3,X2))) (0:6) [cnf transformation 5] % SZS output end Proof for FNE045 ------------------------------ Version: Vampire 1.8 (revision 1280) Termination reason: Refutation Active clauses: 11 Passive clauses: 43 Generated clauses: 60 Final active clauses: 11 Final passive clauses: 30 Input formulas: 1 Initial clauses: 5 Simple tautologies: 1 Forward subsumptions: 10 Binary resolution: 8 Unit resulting resolution: 58 SAT solver clauses: 54 SAT solver unit clauses: 48 SAT solver binary clauses: 4 Memory used [KB]: 255 Time elapsed: 0.0000 s ------------------------------ WATCH: 0.00 CPU 0.01 WC % Success in time 0.003 s WATCH: 0.00 CPU 0.03 WC FINAL WATCH: 0.00 CPU 0.03 WC