src/ZF/Bool.thy
 author lcp Fri Dec 23 16:49:48 1994 +0100 (1994-12-23 ago) changeset 837 778f01546669 parent 799 13aa1e3d8a3a child 1401 0c439768f45c permissions -rw-r--r--
Re-indented declarations; declared the number 2
```     1 (*  Title: 	ZF/bool.thy
```
```     2     ID:         \$Id\$
```
```     3     Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
```
```     4     Copyright   1992  University of Cambridge
```
```     5
```
```     6 Booleans in Zermelo-Fraenkel Set Theory
```
```     7
```
```     8 2 is equal to bool, but serves a different purpose
```
```     9 *)
```
```    10
```
```    11 Bool = ZF + "simpdata" +
```
```    12 consts
```
```    13     "1"		:: "i"     	   ("1")
```
```    14     "2"         :: "i"             ("2")
```
```    15     bool        :: "i"
```
```    16     cond        :: "[i,i,i]=>i"
```
```    17     not		:: "i=>i"
```
```    18     "and"       :: "[i,i]=>i"      (infixl 70)
```
```    19     or		:: "[i,i]=>i"      (infixl 65)
```
```    20     xor		:: "[i,i]=>i"      (infixl 65)
```
```    21
```
```    22 translations
```
```    23    "1"  == "succ(0)"
```
```    24    "2"  == "succ(1)"
```
```    25
```
```    26 defs
```
```    27     bool_def	"bool == {0,1}"
```
```    28     cond_def	"cond(b,c,d) == if(b=1,c,d)"
```
```    29     not_def	"not(b) == cond(b,0,1)"
```
```    30     and_def	"a and b == cond(a,b,0)"
```
```    31     or_def	"a or b == cond(a,1,b)"
```
```    32     xor_def	"a xor b == cond(a,not(b),b)"
```
```    33 end
```