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Definition df-un 3314
Description: Define the union of two classes. Definition 5.6 of [TakeutiZaring] ?Error: 1 , 3 } u. { 1 , 8 } ) = { 1 , 3 , 8 } ^ This math symbol is not active (i.e. was not declared in this scope). p. 16. For example, ({1,3}u.{1,8})={1,3,8} (ex-un 21783). Contrast this operation with difference (df-dif 3312) and intersection (df-in 3316). For an alternate definition in terms of class difference, requiring no dummy variables, see dfun2 3564. For union defined in terms of intersection, see dfun3 3567. (Contributed by NM, 23-Aug-1993.)
Assertion
Ref Expression
df-un
Distinct variable groups:   ,   ,

Detailed syntax breakdown of Definition df-un
StepHypRef Expression
1 cA . . 3
2 cB . . 3
31, 2cun 3307 . 2
4 vx . . . . . 6
54cv 1653 . . . . 5
65, 1wcel 1728 . . . 4
75, 2wcel 1728 . . . 4
86, 7wo 359 . . 3
98, 4cab 2429 . 2
103, 9wceq 1654 1
Colors of variables: wff set class
This definition is referenced by:  elun  3477  nfun  3492  unipr  4056  iinuni  4205  fvclss  6028  bnj98  29479
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