%------------------------------------------------------------------------------ % File : Otter---3.3 % Problem : SWX228-1 : TPTP v9.3.0. Released v9.3.0. % Transfm : none % Format : tptp:raw % Command : otter-tptp-script %s % Computer : n026.cluster.edu % Model : x86_64 x86_64 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 2.10GHz % Memory : 8042.1875MB % OS : Linux 3.10.0-693.el7.x86_64 % CPULimit : 300s % WCLimit : 300s % DateTime : Tue May 5 07:05:28 PM UTC 2026 % Result : Unknown 2.03s 2.26s % Output : None % Verified : % SZS Type : - % Comments : %------------------------------------------------------------------------------ %----No solution output by system %------------------------------------------------------------------------------ %----ORIGINAL SYSTEM OUTPUT % 0.00/0.11 % Problem : SWX228-1 : TPTP v9.3.0. Released v9.3.0. % 0.11/0.12 % Command : otter-tptp-script %s % 0.16/0.33 % Computer : n026.cluster.edu % 0.16/0.33 % Model : x86_64 x86_64 % 0.16/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz % 0.16/0.33 % Memory : 8042.1875MB % 0.16/0.33 % OS : Linux 3.10.0-693.el7.x86_64 % 0.16/0.33 % CPULimit : 300 % 0.16/0.33 % WCLimit : 300 % 0.16/0.33 % DateTime : Tue May 5 12:56:08 EDT 2026 % 0.16/0.33 % CPUTime : % 1.90/2.09 ----- Otter 3.3f, August 2004 ----- % 1.90/2.09 The process was started by sandbox on n026.cluster.edu, % 1.90/2.09 Tue May 5 12:56:08 2026 % 1.90/2.09 The command was "./otter". The process ID is 27326. % 1.90/2.09 % 1.90/2.09 set(prolog_style_variables). % 1.90/2.09 set(auto). % 1.90/2.09 dependent: set(auto1). % 1.90/2.09 dependent: set(process_input). % 1.90/2.09 dependent: clear(print_kept). % 1.90/2.09 dependent: clear(print_new_demod). % 1.90/2.09 dependent: clear(print_back_demod). % 1.90/2.09 dependent: clear(print_back_sub). % 1.90/2.09 dependent: set(control_memory). % 1.90/2.09 dependent: assign(max_mem, 12000). % 1.90/2.09 dependent: assign(pick_given_ratio, 4). % 1.90/2.09 dependent: assign(stats_level, 1). % 1.90/2.09 dependent: assign(max_seconds, 10800). % 1.90/2.09 clear(print_given). % 1.90/2.09 % 1.90/2.09 list(usable). % 1.90/2.09 0 [] A=A. % 1.90/2.09 0 [] aux(Y,Z,Xs,btrue)=union(Xs,Y). % 1.90/2.09 0 [] aux(Y,Z,Xs,bfalse)=cons(Z,union(Xs,Y)). % 1.90/2.09 0 [] barbar(btrue,Y)=btrue. % 1.90/2.09 0 [] barbar(bfalse,Y)=Y. % 1.90/2.09 0 [] e_qNat(s(Z),s(Y2))=e_qNat(Z,Y2). % 1.90/2.09 0 [] e_qNat(s(Z),z)=bfalse. % 1.90/2.09 0 [] e_qNat(z,s(X2))=bfalse. % 1.90/2.09 0 [] e_qNat(z,z)=btrue. % 1.90/2.09 0 [] elem(X,nil)=bfalse. % 1.90/2.09 0 [] elem(X,cons(Z,Xs))=barbar(e_qNat(X,Z),elem(X,Xs)). % 1.90/2.09 0 [] union(nil,Y)=Y. % 1.90/2.09 0 [] union(cons(Z,Xs),Y)=aux(Y,Z,Xs,elem(Z,Y)). % 1.90/2.09 0 [] prop_union_comm(X,Y)=e_q(union(X,Y),union(Y,X)). % 1.90/2.09 0 [] e_q3(bfalse,btrue)=bfalse. % 1.90/2.09 0 [] e_q3(btrue,bfalse)=bfalse. % 1.90/2.09 0 [] e_q2(s(X),s(Y))=e_q2(X,Y). % 1.90/2.09 0 [] e_q2(s(X),z)=bfalse. % 1.90/2.09 0 [] e_q2(z,s(X))=bfalse. % 1.90/2.09 0 [] e_q(X,X)=btrue. % 1.90/2.09 0 [] e_q2(X,X)=btrue. % 1.90/2.09 0 [] e_q3(X,X)=btrue. % 1.90/2.09 0 [] e_q2(X,Z)!=bfalse|e_q(cons(X,Y),cons(Z,X2))=bfalse. % 1.90/2.09 0 [] e_q2(X,Z)!=btrue|e_q(cons(X,Y),cons(Z,X2))=e_q(Y,X2). % 1.90/2.09 0 [] e_q(nil,cons(X,Y))=bfalse. % 1.90/2.09 0 [] e_q(cons(X,Y),nil)=bfalse. % 1.90/2.09 0 [] e_q3(prop_union_comm(X,Y),bfalse)!=btrue. % 1.90/2.09 end_of_list. % 1.90/2.09 % 1.90/2.09 SCAN INPUT: prop=0, horn=1, equality=1, symmetry=0, max_lits=2. % 1.90/2.09 % 1.90/2.09 This is a Horn set with equality. The strategy will be % 1.90/2.09 Knuth-Bendix and hyper_res, with positive clauses in % 1.90/2.09 sos and nonpositive clauses in usable. % 1.90/2.09 % 1.90/2.09 dependent: set(knuth_bendix). % 1.90/2.09 dependent: set(anl_eq). % 1.90/2.09 dependent: set(para_from). % 1.90/2.09 dependent: set(para_into). % 1.90/2.09 dependent: clear(para_from_right). % 1.90/2.09 dependent: clear(para_into_right). % 1.90/2.09 dependent: set(para_from_vars). % 1.90/2.09 dependent: set(eq_units_both_ways). % 1.90/2.09 dependent: set(dynamic_demod_all). % 1.90/2.09 dependent: set(dynamic_demod). % 1.90/2.09 dependent: set(order_eq). % 1.90/2.09 dependent: set(back_demod). % 1.90/2.09 dependent: set(lrpo). % 1.90/2.09 dependent: set(hyper_res). % 1.90/2.09 dependent: clear(order_hyper). % 1.90/2.09 % 1.90/2.09 ------------> process usable: % 1.90/2.09 ** KEPT (pick-wt=14): 1 [] e_q2(A,B)!=bfalse|e_q(cons(A,C),cons(B,D))=bfalse. % 1.90/2.09 ** KEPT (pick-wt=16): 2 [] e_q2(A,B)!=btrue|e_q(cons(A,C),cons(B,D))=e_q(C,D). % 1.90/2.09 ** KEPT (pick-wt=7): 3 [] e_q3(prop_union_comm(A,B),bfalse)!=btrue. % 1.90/2.09 % 1.90/2.09 ------------> process sos: % 1.90/2.09 ** KEPT (pick-wt=3): 4 [] A=A. % 1.90/2.09 ** KEPT (pick-wt=9): 5 [] aux(A,B,C,btrue)=union(C,A). % 1.90/2.09 ** KEPT (pick-wt=11): 7 [copy,6,flip.1] cons(A,union(B,C))=aux(C,A,B,bfalse). % 1.90/2.09 ---> New Demodulator: 8 [new_demod,7] cons(A,union(B,C))=aux(C,A,B,bfalse). % 1.90/2.09 ** KEPT (pick-wt=5): 9 [] barbar(btrue,A)=btrue. % 1.90/2.09 ---> New Demodulator: 10 [new_demod,9] barbar(btrue,A)=btrue. % 1.90/2.09 ** KEPT (pick-wt=5): 11 [] barbar(bfalse,A)=A. % 1.90/2.09 ---> New Demodulator: 12 [new_demod,11] barbar(bfalse,A)=A. % 1.90/2.09 ** KEPT (pick-wt=9): 13 [] e_qNat(s(A),s(B))=e_qNat(A,B). % 1.90/2.09 ---> New Demodulator: 14 [new_demod,13] e_qNat(s(A),s(B))=e_qNat(A,B). % 1.90/2.09 ** KEPT (pick-wt=6): 15 [] e_qNat(s(A),z)=bfalse. % 1.90/2.09 ---> New Demodulator: 16 [new_demod,15] e_qNat(s(A),z)=bfalse. % 1.90/2.09 ** KEPT (pick-wt=6): 17 [] e_qNat(z,s(A))=bfalse. % 1.90/2.09 ---> New Demodulator: 18 [new_demod,17] e_qNat(z,s(A))=bfalse. % 1.90/2.09 ** KEPT (pick-wt=5): 19 [] e_qNat(z,z)=btrue. % 1.90/2.09 ---> New Demodulator: 20 [new_demod,19] e_qNat(z,z)=btrue. % 1.90/2.09 ** KEPT (pick-wt=5): 21 [] elem(A,nil)=bfalse. % 1.90/2.09 ---> New Demodulator: 22 [new_demod,21] elem(A,nil)=bfalse. % 1.90/2.09 ** KEPT (pick-wt=13): 23 [] elem(A,cons(B,C))=barbar(e_qNat(A,B),elem(A,C)). % 1.90/2.09 ---> New Demodulator: 24 [new_demod,23] elem(A,cons(B,C))=barbar(e_qNat(A,B),elem(A,C)). % 1.90/2.09 ** KEPT (pick-wt=5): 25 [] union(nil,A)=A. % 1.90/2.09 ---> New Demodulator: 26 [new_demod,25] union(nil,A)=A. % 1.90/2.09 ** KEPT (pick-wt=13): 27 [] union(cons(A,B),C)=aux(C,A,B,elem(A,C)). % 1.90/2.09 ---> New Demodulator: 28 [new_demod,27] union(cons(A,B),C)=aux(C,A,B,elem(A,C)). % 1.90/2.09 ** KEPT (pick-wt=11): 30 [copy,29,flip.1] e_q(union(A,B),union(B,A))=prop_union_comm(A,B). % 1.90/2.09 ---> New Demodulator: 31 [new_demod,30] e_q(union(A,B),union(B,A))=prop_union_comm(A,B). % 2.03/2.26 ** KEPT (pick-wt=5): 32 [] e_q3(bfalse,btrue)=bfalse. % 2.03/2.26 ---> New Demodulator: 33 [new_demod,32] e_q3(bfalse,btrue)=bfalse. % 2.03/2.26 ** KEPT (pick-wt=5): 34 [] e_q3(btrue,bfalse)=bfalse. % 2.03/2.26 ---> New Demodulator: 35 [new_demod,34] e_q3(btrue,bfalse)=bfalse. % 2.03/2.26 ** KEPT (pick-wt=9): 36 [] e_q2(s(A),s(B))=e_q2(A,B). % 2.03/2.26 ---> New Demodulator: 37 [new_demod,36] e_q2(s(A),s(B))=e_q2(A,B). % 2.03/2.26 ** KEPT (pick-wt=6): 38 [] e_q2(s(A),z)=bfalse. % 2.03/2.26 ---> New Demodulator: 39 [new_demod,38] e_q2(s(A),z)=bfalse. % 2.03/2.26 ** KEPT (pick-wt=6): 40 [] e_q2(z,s(A))=bfalse. % 2.03/2.26 ---> New Demodulator: 41 [new_demod,40] e_q2(z,s(A))=bfalse. % 2.03/2.26 ** KEPT (pick-wt=5): 42 [] e_q(A,A)=btrue. % 2.03/2.26 ---> New Demodulator: 43 [new_demod,42] e_q(A,A)=btrue. % 2.03/2.26 ** KEPT (pick-wt=5): 44 [] e_q2(A,A)=btrue. % 2.03/2.26 ---> New Demodulator: 45 [new_demod,44] e_q2(A,A)=btrue. % 2.03/2.26 ** KEPT (pick-wt=5): 46 [] e_q3(A,A)=btrue. % 2.03/2.26 ---> New Demodulator: 47 [new_demod,46] e_q3(A,A)=btrue. % 2.03/2.26 ** KEPT (pick-wt=7): 48 [] e_q(nil,cons(A,B))=bfalse. % 2.03/2.26 ---> New Demodulator: 49 [new_demod,48] e_q(nil,cons(A,B))=bfalse. % 2.03/2.26 ** KEPT (pick-wt=7): 50 [] e_q(cons(A,B),nil)=bfalse. % 2.03/2.26 ---> New Demodulator: 51 [new_demod,50] e_q(cons(A,B),nil)=bfalse. % 2.03/2.26 Following clause subsumed by 4 during input processing: 0 [copy,4,flip.1] A=A. % 2.03/2.26 ** KEPT (pick-wt=9): 52 [copy,5,flip.1] union(A,B)=aux(B,C,A,btrue). % 2.03/2.26 >>>> Starting back demodulation with 8. % 2.03/2.26 >>>> Starting back demodulation with 10. % 2.03/2.26 >>>> Starting back demodulation with 12. % 2.03/2.26 >>>> Starting back demodulation with 14. % 2.03/2.26 >>>> Starting back demodulation with 16. % 2.03/2.26 >>>> Starting back demodulation with 18. % 2.03/2.26 >>>> Starting back demodulation with 20. % 2.03/2.26 >>>> Starting back demodulation with 22. % 2.03/2.26 >>>> Starting back demodulation with 24. % 2.03/2.26 >>>> Starting back demodulation with 26. % 2.03/2.26 >>>> Starting back demodulation with 28. % 2.03/2.26 >>>> Starting back demodulation with 31. % 2.03/2.26 >>>> Starting back demodulation with 33. % 2.03/2.26 >>>> Starting back demodulation with 35. % 2.03/2.26 >>>> Starting back demodulation with 37. % 2.03/2.26 >>>> Starting back demodulation with 39. % 2.03/2.26 >>>> Starting back demodulation with 41. % 2.03/2.26 >>>> Starting back demodulation with 43. % 2.03/2.26 >>>> Starting back demodulation with 45. % 2.03/2.26 >>>> Starting back demodulation with 47. % 2.03/2.26 >>>> Starting back demodulation with 49. % 2.03/2.26 >>>> Starting back demodulation with 51. % 2.03/2.26 Following clause subsumed by 5 during input processing: 0 [copy,52,flip.1] aux(A,B,C,btrue)=union(C,A). % 2.03/2.26 % 2.03/2.26 ======= end of input processing ======= % 2.03/2.26 % 2.03/2.26 =========== start of search =========== % 2.03/2.26 % 2.03/2.26 % 2.03/2.26 Resetting weight limit to 17. % 2.03/2.26 % 2.03/2.26 % 2.03/2.26 Resetting weight limit to 17. % 2.03/2.26 % 2.03/2.26 sos_size=161 % 2.03/2.26 % 2.03/2.26 Search stopped because sos empty. % 2.03/2.26 % 2.03/2.26 % 2.03/2.26 Search stopped because sos empty. % 2.03/2.26 % 2.03/2.26 ============ end of search ============ % 2.03/2.26 % 2.03/2.26 -------------- statistics ------------- % 2.03/2.26 clauses given 301 % 2.03/2.26 clauses generated 11822 % 2.03/2.26 clauses kept 400 % 2.03/2.26 clauses forward subsumed 3022 % 2.03/2.26 clauses back subsumed 92 % 2.03/2.26 Kbytes malloced 6835 % 2.03/2.26 % 2.03/2.26 ----------- times (seconds) ----------- % 2.03/2.26 user CPU time 0.16 (0 hr, 0 min, 0 sec) % 2.03/2.26 system CPU time 0.01 (0 hr, 0 min, 0 sec) % 2.03/2.26 wall-clock time 2 (0 hr, 0 min, 2 sec) % 2.03/2.26 % 2.03/2.26 Process 27326 finished Tue May 5 12:56:10 2026 % 2.03/2.26 Otter interrupted % 2.03/2.26 PROOF NOT FOUND %------------------------------------------------------------------------------