src/ZF/Sum.thy
author clasohm
Tue Feb 06 12:27:17 1996 +0100 (1996-02-06)
changeset 1478 2b8c2a7547ab
parent 1401 0c439768f45c
child 2469 b50b8c0eec01
permissions -rw-r--r--
expanded tabs
     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 + "simpdata" +
    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 defs
    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) == (%<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