src/ZF/Sum.thy
 author lcp Tue Nov 29 00:31:31 1994 +0100 (1994-11-29) changeset 753 ec86863e87c8 parent 124 858ab9a9b047 child 1108 22b256c8c9fb permissions -rw-r--r--
replaced "rules" by "defs"
```     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) == 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
```