src/FOLP/ex/Quantifiers_Cla.thy

tuned signature: more explicit operations;

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−(*  Title:      FOLP/ex/Quantifiers_Cla.thy
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−    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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−    Copyright   1991  University of Cambridge
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−
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−First-Order Logic: quantifier examples (intuitionistic and classical)
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−Needs declarations of the theory "thy" and the tactic "tac".
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−*)
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−
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−theory Quantifiers_Cla
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−imports FOLP
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−begin
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−
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−schematic_goal "?p : (ALL x y. P(x,y))  -->  (ALL y x. P(x,y))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−schematic_goal "?p : (EX x y. P(x,y)) --> (EX y x. P(x,y))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−(*Converse is false*)
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−schematic_goal "?p : (ALL x. P(x)) | (ALL x. Q(x)) --> (ALL x. P(x) | Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−schematic_goal "?p : (ALL x. P-->Q(x))  <->  (P--> (ALL x. Q(x)))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−schematic_goal "?p : (ALL x. P(x)-->Q)  <->  ((EX x. P(x)) --> Q)"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−text "Some harder ones"
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−
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−schematic_goal "?p : (EX x. P(x) | Q(x)) <-> (EX x. P(x)) | (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−(*Converse is false*)
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−schematic_goal "?p : (EX x. P(x)&Q(x)) --> (EX x. P(x))  &  (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−text "Basic test of quantifier reasoning"
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−(*TRUE*)
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−schematic_goal "?p : (EX y. ALL x. Q(x,y)) -->  (ALL x. EX y. Q(x,y))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−schematic_goal "?p : (ALL x. Q(x))  -->  (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−text "The following should fail, as they are false!"
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−
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−schematic_goal "?p : (ALL x. EX y. Q(x,y))  -->  (EX y. ALL x. Q(x,y))"
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−  apply (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)?
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−  oops
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−
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−schematic_goal "?p : (EX x. Q(x))  -->  (ALL x. Q(x))"
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−  apply (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)?
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−  oops
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−
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−schematic_goal "?p : P(?a) --> (ALL x. P(x))"
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−  apply (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)?
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−  oops
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−
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−schematic_goal "?p : (P(?a) --> (ALL x. Q(x))) --> (ALL x. P(x) --> Q(x))"
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−  apply (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)?
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−  oops
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−
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−
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−text "Back to things that are provable..."
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−
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−schematic_goal "?p : (ALL x. P(x)-->Q(x)) & (EX x. P(x)) --> (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−(*An example of why exI should be delayed as long as possible*)
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−schematic_goal "?p : (P --> (EX x. Q(x))) & P --> (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−schematic_goal "?p : (ALL x. P(x)-->Q(f(x))) & (ALL x. Q(x)-->R(g(x))) & P(d) --> R(?a)"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−schematic_goal "?p : (ALL x. Q(x))  -->  (EX x. Q(x))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−
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−text "Some slow ones"
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−
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−(*Principia Mathematica *11.53  *)
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−schematic_goal "?p : (ALL x y. P(x) --> Q(y)) <-> ((EX x. P(x)) --> (ALL y. Q(y)))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−(*Principia Mathematica *11.55  *)
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−schematic_goal "?p : (EX x y. P(x) & Q(x,y)) <-> (EX x. P(x) & (EX y. Q(x,y)))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−(*Principia Mathematica *11.61  *)
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−schematic_goal "?p : (EX y. ALL x. P(x) --> Q(x,y)) --> (ALL x. P(x) --> (EX y. Q(x,y)))"
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−  by (tactic \<open>Cla.fast_tac \<^context> FOLP_cs 1\<close>)
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−
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−end