Theorem orduniss 3076

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 2962	. 2 |- (Ord A -> Tr A)
2		df-tr 2681	. 2 |- (Tr A <-> U.A (_ A)
3	1, 2	sylib 198	1 |- (Ord A -> U.A (_ A)

Syntax hints:   -> wi 3   (_ wss 2047  U.cuni 2503  Tr wtr 2680  Ord word 2947

This theorem is referenced by:  orduniorsuc 3087  rankuniss 4701

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 2681  df-ord 2951

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