src/FOL/IFOL.thy
author clasohm
Thu Oct 05 14:45:54 1995 +0100 (1995-10-05)
changeset 1268 f6ef556b3ede
parent 928 cb31a4e97f75
child 1322 9b3d3362a048
permissions -rw-r--r--
corrected title
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(*  Title:      FOL/IFOL.thy
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1993  University of Cambridge
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Intuitionistic first-order logic
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*)
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IFOL = Pure +
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classes
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  term < logic
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default
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  term
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types
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  o
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arities
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  o :: logic
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consts
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  Trueprop      :: "o => prop"                  ("(_)" 5)
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  True, False   :: "o"
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  (* Connectives *)
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  "="           :: "['a, 'a] => o"              (infixl 50)
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  Not           :: "o => o"                     ("~ _" [40] 40)
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  "&"           :: "[o, o] => o"                (infixr 35)
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  "|"           :: "[o, o] => o"                (infixr 30)
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  "-->"         :: "[o, o] => o"                (infixr 25)
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  "<->"         :: "[o, o] => o"                (infixr 25)
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  (* Quantifiers *)
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  All           :: "('a => o) => o"             (binder "ALL " 10)
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  Ex            :: "('a => o) => o"             (binder "EX " 10)
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  Ex1           :: "('a => o) => o"             (binder "EX! " 10)
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syntax
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  "~="          :: "['a, 'a] => o"              (infixl 50)
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translations
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  "x ~= y"      == "~ (x = y)"
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rules
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  (* Equality *)
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  refl          "a=a"
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  subst         "[| a=b;  P(a) |] ==> P(b)"
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  (* Propositional logic *)
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  conjI         "[| P;  Q |] ==> P&Q"
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  conjunct1     "P&Q ==> P"
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  conjunct2     "P&Q ==> Q"
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  disjI1        "P ==> P|Q"
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  disjI2        "Q ==> P|Q"
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  disjE         "[| P|Q;  P ==> R;  Q ==> R |] ==> R"
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  impI          "(P ==> Q) ==> P-->Q"
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  mp            "[| P-->Q;  P |] ==> Q"
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  FalseE        "False ==> P"
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  (* Definitions *)
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  True_def      "True  == False-->False"
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  not_def       "~P    == P-->False"
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  iff_def       "P<->Q == (P-->Q) & (Q-->P)"
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  (* Unique existence *)
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  ex1_def       "EX! x. P(x) == EX x. P(x) & (ALL y. P(y) --> y=x)"
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  (* Quantifiers *)
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  allI          "(!!x. P(x)) ==> (ALL x.P(x))"
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  spec          "(ALL x.P(x)) ==> P(x)"
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  exI           "P(x) ==> (EX x.P(x))"
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  exE           "[| EX x.P(x);  !!x. P(x) ==> R |] ==> R"
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  (* Reflection *)
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  eq_reflection   "(x=y)   ==> (x==y)"
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  iff_reflection  "(P<->Q) ==> (P==Q)"
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end
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