Theorem elun1 2197

Description: Membership law for union of classes.

Assertion

Ref	Expression
elun1	|- (A e. B -> A e. (B u. C))

Proof of Theorem elun1

Step	Hyp	Ref	Expression
1		ssun1 2193	. 2 |- B (_ (B u. C)
2	1	sseli 2065	1 |- (A e. B -> A e. (B u. C))

Syntax hints:   -> wi 3   e. wcel 958   u. cun 2045

This theorem is referenced by:  tpi1 2455  tpi2 2456  erthdm 4283  rankun 4691  rankelun 4707  xrsupexmnf 6074  xrinfmexpnf 6075  shslej 9338  cnfilca 10583  cnfilcaOLD 10584

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 962  ax-gen 963  ax-8 964  ax-10 966  ax-12 968  ax-17 971  ax-4 973  ax-5o 975  ax-6o 978  ax-9o 1123  ax-10o 1140  ax-16 1210  ax-11o 1218  ax-ext 1459

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-ex 981  df-sb 1172  df-clab 1464  df-cleq 1469  df-clel 1472  df-v 1812  df-un 2050  df-in 2051  df-ss 2053

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