src/ZF/Sum.thy
author clasohm
Thu Sep 16 12:20:38 1993 +0200 (1993-09-16)
changeset 0 a5a9c433f639
child 124 858ab9a9b047
permissions -rw-r--r--
Initial revision
     1 (*  Title: 	ZF/sum.thy
     2     ID:         $Id$
     3     Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
     4     Copyright   1993  University of Cambridge
     5 
     6 Disjoint sums in Zermelo-Fraenkel Set Theory 
     7 "Part" primitive for simultaneous recursive type definitions
     8 *)
     9 
    10 Sum = Bool +
    11 consts
    12     "+"    	:: "[i,i]=>i"      		(infixr 65)
    13     Inl,Inr     :: "i=>i"
    14     case        :: "[i=>i, i=>i, i]=>i"
    15     Part        :: "[i,i=>i] => i"
    16 
    17 rules
    18     sum_def     "A+B == {0}*A Un {1}*B"
    19     Inl_def     "Inl(a) == <0,a>"
    20     Inr_def     "Inr(b) == <1,b>"
    21     case_def    "case(c,d) == split(%y z. cond(y, d(z), c(z)))"
    22 
    23   (*operator for selecting out the various summands*)
    24     Part_def	"Part(A,h) == {x: A. EX z. x = h(z)}"
    25 end