doc-src/ZF/FOL-eg.txt
author paulson
Wed, 13 Jan 1999 16:36:36 +0100
changeset 6121 5fe77b9b5185
permissions -rw-r--r--
the separate FOL and ZF logics manual, with new material on datatypes and
inductive definitions
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(**** FOL examples ****)
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Pretty.setmargin 72;  (*existing macros just allow this margin*)
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print_depth 0;
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(*** Intuitionistic examples ***)
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context IFOL.thy;
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(*Quantifier example from Logic&Computation*)
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Goal "(EX y. ALL x. Q(x,y)) -->  (ALL x. EX y. Q(x,y))";
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by (resolve_tac [impI] 1);
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by (resolve_tac [allI] 1);
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by (resolve_tac [exI] 1);
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by (eresolve_tac [exE] 1);
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choplev 2;
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by (eresolve_tac [exE] 1);
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by (resolve_tac [exI] 1);
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by (eresolve_tac [allE] 1);
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by (assume_tac 1);
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(*Example of Dyckhoff's method*)
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Goalw [not_def] "~ ~ ((P-->Q) | (Q-->P))";
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by (resolve_tac [impI] 1);
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by (eresolve_tac [disj_impE] 1);
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by (eresolve_tac [imp_impE] 1);
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by (eresolve_tac [imp_impE] 1);
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by (REPEAT (eresolve_tac [FalseE] 2));
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by (assume_tac 1);
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(*** Classical examples ***)
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context FOL.thy;
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Goal "EX y. ALL x. P(y)-->P(x)";
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by (resolve_tac [exCI] 1);
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by (resolve_tac [allI] 1);
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by (resolve_tac [impI] 1);
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by (eresolve_tac [allE] 1);
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prth (allI RSN (2,swap));
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by (eresolve_tac [it] 1);
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by (resolve_tac [impI] 1);
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by (eresolve_tac [notE] 1);
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by (assume_tac 1);
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Goal "EX y. ALL x. P(y)-->P(x)";
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by (Blast_tac 1);
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- Goal "EX y. ALL x. P(y)-->P(x)";
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Level 0
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EX y. ALL x. P(y) --> P(x)
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 1. EX y. ALL x. P(y) --> P(x)
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- by (resolve_tac [exCI] 1);
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Level 1
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EX y. ALL x. P(y) --> P(x)
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 1. ALL y. ~(ALL x. P(y) --> P(x)) ==> ALL x. P(?a) --> P(x)
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- by (resolve_tac [allI] 1);
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Level 2
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EX y. ALL x. P(y) --> P(x)
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 1. !!x. ALL y. ~(ALL x. P(y) --> P(x)) ==> P(?a) --> P(x)
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- by (resolve_tac [impI] 1);
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Level 3
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EX y. ALL x. P(y) --> P(x)
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 1. !!x. [| ALL y. ~(ALL x. P(y) --> P(x)); P(?a) |] ==> P(x)
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- by (eresolve_tac [allE] 1);
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Level 4
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EX y. ALL x. P(y) --> P(x)
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 1. !!x. [| P(?a); ~(ALL xa. P(?y3(x)) --> P(xa)) |] ==> P(x)
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- prth (allI RSN (2,swap));
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[| ~(ALL x. ?P1(x)); !!x. ~?Q ==> ?P1(x) |] ==> ?Q
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- by (eresolve_tac [it] 1);
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Level 5
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EX y. ALL x. P(y) --> P(x)
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 1. !!x xa. [| P(?a); ~P(x) |] ==> P(?y3(x)) --> P(xa)
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- by (resolve_tac [impI] 1);
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Level 6
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EX y. ALL x. P(y) --> P(x)
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 1. !!x xa. [| P(?a); ~P(x); P(?y3(x)) |] ==> P(xa)
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- by (eresolve_tac [notE] 1);
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Level 7
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EX y. ALL x. P(y) --> P(x)
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 1. !!x xa. [| P(?a); P(?y3(x)) |] ==> P(x)
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- by (assume_tac 1);
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Level 8
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EX y. ALL x. P(y) --> P(x)
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No subgoals!
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- Goal "EX y. ALL x. P(y)-->P(x)";
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Level 0
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EX y. ALL x. P(y) --> P(x)
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 1. EX y. ALL x. P(y) --> P(x)
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- by (best_tac FOL_dup_cs 1);
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Level 1
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EX y. ALL x. P(y) --> P(x)
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No subgoals!
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(**** finally, the example FOL/ex/if.ML ****)
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> val prems = goalw if_thy [if_def]
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#    "[| P ==> Q; ~P ==> R |] ==> if(P,Q,R)";
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Level 0
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if(P,Q,R)
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 1. P & Q | ~P & R
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> by (Classical.fast_tac (FOL_cs addIs prems) 1);
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Level 1
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if(P,Q,R)
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No subgoals!
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> val ifI = result();
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> val major::prems = goalw if_thy [if_def]
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#    "[| if(P,Q,R);  [| P; Q |] ==> S; [| ~P; R |] ==> S |] ==> S";
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Level 0
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S
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 1. S
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> by (cut_facts_tac [major] 1);
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Level 1
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S
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 1. P & Q | ~P & R ==> S
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> by (Classical.fast_tac (FOL_cs addIs prems) 1);
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Level 2
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S
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No subgoals!
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> val ifE = result();
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> goal if_thy "if(P, if(Q,A,B), if(Q,C,D)) <-> if(Q, if(P,A,C), if(P,B,D))";
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Level 0
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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> by (resolve_tac [iffI] 1);
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Level 1
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. if(P,if(Q,A,B),if(Q,C,D)) ==> if(Q,if(P,A,C),if(P,B,D))
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 2. if(Q,if(P,A,C),if(P,B,D)) ==> if(P,if(Q,A,B),if(Q,C,D))
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> by (eresolve_tac [ifE] 1);
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Level 2
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. [| P; if(Q,A,B) |] ==> if(Q,if(P,A,C),if(P,B,D))
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 2. [| ~P; if(Q,C,D) |] ==> if(Q,if(P,A,C),if(P,B,D))
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 3. if(Q,if(P,A,C),if(P,B,D)) ==> if(P,if(Q,A,B),if(Q,C,D))
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> by (eresolve_tac [ifE] 1);
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Level 3
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. [| P; Q; A |] ==> if(Q,if(P,A,C),if(P,B,D))
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 2. [| P; ~Q; B |] ==> if(Q,if(P,A,C),if(P,B,D))
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 3. [| ~P; if(Q,C,D) |] ==> if(Q,if(P,A,C),if(P,B,D))
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 4. if(Q,if(P,A,C),if(P,B,D)) ==> if(P,if(Q,A,B),if(Q,C,D))
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> by (resolve_tac [ifI] 1);
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Level 4
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. [| P; Q; A; Q |] ==> if(P,A,C)
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 2. [| P; Q; A; ~Q |] ==> if(P,B,D)
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 3. [| P; ~Q; B |] ==> if(Q,if(P,A,C),if(P,B,D))
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 4. [| ~P; if(Q,C,D) |] ==> if(Q,if(P,A,C),if(P,B,D))
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 5. if(Q,if(P,A,C),if(P,B,D)) ==> if(P,if(Q,A,B),if(Q,C,D))
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> by (resolve_tac [ifI] 1);
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Level 5
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. [| P; Q; A; Q; P |] ==> A
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 2. [| P; Q; A; Q; ~P |] ==> C
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 3. [| P; Q; A; ~Q |] ==> if(P,B,D)
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 4. [| P; ~Q; B |] ==> if(Q,if(P,A,C),if(P,B,D))
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 5. [| ~P; if(Q,C,D) |] ==> if(Q,if(P,A,C),if(P,B,D))
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 6. if(Q,if(P,A,C),if(P,B,D)) ==> if(P,if(Q,A,B),if(Q,C,D))
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> choplev 0;
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Level 0
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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 1. if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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> val if_cs = FOL_cs addSIs [ifI] addSEs[ifE];
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> by (Classical.fast_tac if_cs 1);
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Level 1
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if(P,if(Q,A,B),if(Q,C,D)) <-> if(Q,if(P,A,C),if(P,B,D))
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No subgoals!
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> val if_commute = result();
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> goal if_thy "if(if(P,Q,R), A, B) <-> if(P, if(Q,A,B), if(R,A,B))";
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Level 0
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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 1. if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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> by (Classical.fast_tac if_cs 1);
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Level 1
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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No subgoals!
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> val nested_ifs = result();
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> choplev 0;
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Level 0
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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 1. if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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> by (rewrite_goals_tac [if_def]);
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Level 1
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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 1. (P & Q | ~P & R) & A | ~(P & Q | ~P & R) & B <->
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    P & (Q & A | ~Q & B) | ~P & (R & A | ~R & B)
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> by (Classical.fast_tac FOL_cs 1);
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Level 2
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,A,B))
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No subgoals!
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> goal if_thy "if(if(P,Q,R), A, B) <-> if(P, if(Q,A,B), if(R,B,A))";
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Level 0
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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 1. if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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> by (REPEAT (Classical.step_tac if_cs 1));
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Level 1
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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 1. [| A; ~P; R; ~P; R |] ==> B
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 2. [| B; ~P; ~R; ~P; ~R |] ==> A
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 3. [| ~P; R; B; ~P; R |] ==> A
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 4. [| ~P; ~R; A; ~B; ~P |] ==> R
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> choplev 0;
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Level 0
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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 1. if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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> by (rewrite_goals_tac [if_def]);
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Level 1
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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 1. (P & Q | ~P & R) & A | ~(P & Q | ~P & R) & B <->
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    P & (Q & A | ~Q & B) | ~P & (R & B | ~R & A)
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> by (Classical.fast_tac FOL_cs 1);
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by: tactic failed
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Exception- ERROR raised
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Exception failure raised
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> by (REPEAT (Classical.step_tac FOL_cs 1));
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Level 2
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if(if(P,Q,R),A,B) <-> if(P,if(Q,A,B),if(R,B,A))
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 1. [| A; ~P; R; ~P; R; ~False |] ==> B
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 2. [| A; ~P; R; R; ~False; ~B; ~B |] ==> Q
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 3. [| B; ~P; ~R; ~P; ~A |] ==> R
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 4. [| B; ~P; ~R; ~Q; ~A |] ==> R
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 5. [| B; ~R; ~P; ~A; ~R; Q; ~False |] ==> A
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 6. [| ~P; R; B; ~P; R; ~False |] ==> A
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 7. [| ~P; ~R; A; ~B; ~R |] ==> P
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 8. [| ~P; ~R; A; ~B; ~R |] ==> Q