Theorem unv 3461

Description: The union of a class with the universal class is the universal class. Exercise 4.10(l) of [Mendelson] p. 231. (Contributed by NM, 17-May-1998.)

Assertion

Ref	Expression
unv	|- ( A u. _V ) = _V

Proof of Theorem unv

Step	Hyp	Ref	Expression
1		ssv 3178	. 2 |- ( A u. _V ) C_ _V
2		ssun2 3300	. 2 |- _V C_ ( A u. _V )
3	1, 2	eqssi 3172	1 |- ( A u. _V ) = _V

Syntax hints:   = wceq 1353   _Vcvv 2738   u. cun 3128

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-v 2740  df-un 3134  df-in 3136  df-ss 3143

This theorem is referenced by: (None)