src/ZF/Sum.thy
changeset 0 a5a9c433f639
child 124 858ab9a9b047
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/ZF/Sum.thy	Thu Sep 16 12:20:38 1993 +0200
     1.3 @@ -0,0 +1,25 @@
     1.4 +(*  Title: 	ZF/sum.thy
     1.5 +    ID:         $Id$
     1.6 +    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
     1.7 +    Copyright   1993  University of Cambridge
     1.8 +
     1.9 +Disjoint sums in Zermelo-Fraenkel Set Theory 
    1.10 +"Part" primitive for simultaneous recursive type definitions
    1.11 +*)
    1.12 +
    1.13 +Sum = Bool +
    1.14 +consts
    1.15 +    "+"    	:: "[i,i]=>i"      		(infixr 65)
    1.16 +    Inl,Inr     :: "i=>i"
    1.17 +    case        :: "[i=>i, i=>i, i]=>i"
    1.18 +    Part        :: "[i,i=>i] => i"
    1.19 +
    1.20 +rules
    1.21 +    sum_def     "A+B == {0}*A Un {1}*B"
    1.22 +    Inl_def     "Inl(a) == <0,a>"
    1.23 +    Inr_def     "Inr(b) == <1,b>"
    1.24 +    case_def    "case(c,d) == split(%y z. cond(y, d(z), c(z)))"
    1.25 +
    1.26 +  (*operator for selecting out the various summands*)
    1.27 +    Part_def	"Part(A,h) == {x: A. EX z. x = h(z)}"
    1.28 +end