src/ZF/ex/contract0.thy
 changeset 0 a5a9c433f639 child 16 0b033d50ca1c
```     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/ZF/ex/contract0.thy	Thu Sep 16 12:20:38 1993 +0200
1.3 @@ -0,0 +1,36 @@
1.4 +(*  Title: 	ZF/ex/contract.thy
1.5 +    ID:         \$Id\$
1.6 +    Author: 	Tobias Nipkow & Lawrence C Paulson
1.7 +    Copyright   1993  University of Cambridge
1.8 +
1.9 +Inductive definition of (1-step) contractions and (mult-step) reductions
1.10 +*)
1.11 +
1.12 +Contract0 = Comb +
1.13 +consts
1.14 +  diamond   :: "i => o"
1.15 +  I         :: "i"
1.16 +
1.17 +  contract  :: "i"
1.18 +  "-1->"    :: "[i,i] => o"    			(infixl 50)
1.19 +  "--->"    :: "[i,i] => o"    			(infixl 50)
1.20 +
1.21 +  parcontract :: "i"
1.22 +  "=1=>"    :: "[i,i] => o"    			(infixl 50)
1.23 +  "===>"    :: "[i,i] => o"    			(infixl 50)
1.24 +
1.25 +translations
1.26 +  "p -1-> q" == "<p,q> : contract"
1.27 +  "p ---> q" == "<p,q> : contract^*"
1.28 +  "p =1=> q" == "<p,q> : parcontract"
1.29 +  "p ===> q" == "<p,q> : parcontract^+"
1.30 +
1.31 +rules
1.32 +
1.33 +  diamond_def "diamond(r) == ALL x y. <x,y>:r --> \
1.34 +\                            (ALL y'. <x,y'>:r --> \
1.35 +\                                 (EX z. <y,z>:r & <y',z> : r))"
1.36 +
1.37 +  I_def       "I == S#K#K"
1.38 +
1.39 +end
```