Theorem limuni2 4944

Description: The union of a limit ordinal is a limit ordinal. (Contributed by NM, 19-Sep-2006.)

Assertion

Ref	Expression
limuni2

Proof of Theorem limuni2

Step	Hyp	Ref	Expression
1		limuni 4943	. . 3
2		limeq 4895	. . 3
3	1, 2	syl 16	. 2
4	3	ibi 241	1

Syntax hints:  ->wi 4  <->wb 184  =wceq 1395  U.cuni 4249  Limwlim 4884

This theorem is referenced by:  rankxplim2  8319  rankxplim3  8320

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1618  ax-4 1631  ax-5 1704  ax-6 1747  ax-7 1790  ax-10 1837  ax-11 1842  ax-12 1854  ax-13 1999  ax-ext 2435

This theorem depends on definitions:  df-bi 185  df-an 371  df-3an 975  df-tru 1398  df-ex 1613  df-nf 1617  df-sb 1740  df-clab 2443  df-cleq 2449  df-clel 2452  df-nfc 2607  df-ne 2654  df-ral 2812  df-rex 2813  df-in 3482  df-ss 3489  df-uni 4250  df-tr 4546  df-po 4805  df-so 4806  df-fr 4843  df-we 4845  df-ord 4886  df-lim 4888