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\$
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```     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 *)
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```     9
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```    10 Sum = Bool + equalities +
```
```    11
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```    12 global
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```    13
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```    14 consts
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```    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
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```    21 local
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```    22
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```    23 defs
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```    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
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```    29   (*operator for selecting out the various summands*)
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```    30     Part_def    "Part(A,h) == {x: A. EX z. x = h(z)}"
```
```    31 end
```