src/ZF/Sum.thy
 changeset 0 a5a9c433f639 child 124 858ab9a9b047
equal inserted replaced
-1:000000000000 0:a5a9c433f639
`       `
`     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 +`
`       `
`    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 rules`
`       `
`    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`