src/ZF/Sum.thy
author paulson
Tue Jun 18 18:45:07 2002 +0200 (2002-06-18)
changeset 13220 62c899c77151
parent 5325 f7a5e06adea1
child 13240 bb5f4faea1f3
permissions -rw-r--r--
tidying
     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 + equalities + 
    11 
    12 global
    13 
    14 consts
    15     "+"     :: "[i,i]=>i"                     (infixr 65)
    16     Inl     :: "i=>i"
    17     Inr     :: "i=>i"
    18     "case"  :: "[i=>i, i=>i, i]=>i"
    19     Part    :: "[i,i=>i] => i"
    20 
    21 local
    22 
    23 defs
    24     sum_def     "A+B == {0}*A Un {1}*B"
    25     Inl_def     "Inl(a) == <0,a>"
    26     Inr_def     "Inr(b) == <1,b>"
    27     case_def    "case(c,d) == (%<y,z>. cond(y, d(z), c(z)))"
    28 
    29   (*operator for selecting out the various summands*)
    30     Part_def    "Part(A,h) == {x: A. EX z. x = h(z)}"
    31 end