Theorem orduniss 3082

Description: An ordinal class includes its union.

Assertion

Ref	Expression
orduniss	|- (Ord A -> U.A (_ A)

Proof of Theorem orduniss

Step	Hyp	Ref	Expression
1		ordtr 2968	. 2 |- (Ord A -> Tr A)
2		df-tr 2686	. 2 |- (Tr A <-> U.A (_ A)
3	1, 2	sylib 198	1 |- (Ord A -> U.A (_ A)

Syntax hints:   -> wi 3   (_ wss 2050  U.cuni 2507  Tr wtr 2685  Ord word 2953

This theorem is referenced by:  orduniorsuc 3093  rankuniss 4711

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-an 225  df-tr 2686  df-ord 2957

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