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Definition df-uni 3892
 Description: Define the union of a class i.e. the collection of all members of the members of the class. Definition 5.5 of [TakeutiZaring] p. 16. For example, ∪{{ 1 , 3 }, { 1 , 8 }} = { 1 , 3 , 8 } (ex-uni in set.mm). This is similar to the union of two classes df-un 3214. (Contributed by NM, 23-Aug-1993.)
Assertion
Ref Expression
df-uni A = {x y(x y y A)}
Distinct variable group:   x,y,A

Detailed syntax breakdown of Definition df-uni
StepHypRef Expression
1 cA . . 3 class A
21cuni 3891 . 2 class A
3 vx . . . . . 6 setvar x
4 vy . . . . . 6 setvar y
53, 4wel 1711 . . . . 5 wff x y
64cv 1641 . . . . . 6 class y
76, 1wcel 1710 . . . . 5 wff y A
85, 7wa 358 . . . 4 wff (x y y A)
98, 4wex 1541 . . 3 wff y(x y y A)
109, 3cab 2339 . 2 class {x y(x y y A)}
112, 10wceq 1642 1 wff A = {x y(x y y A)}
 Colors of variables: wff setvar class This definition is referenced by:  dfuni2  3893  eluni  3894  csbunig  3899
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