Theorem 19.31 1968

Description: Theorem 19.31 of [Margaris] p. 90. See 19.31v 1731 for a version requiring fewer axioms. (Contributed by NM, 14-May-1993.)

Hypothesis

Ref	Expression
19.31.1

Assertion

Ref	Expression
19.31

Proof of Theorem 19.31

Step	Hyp	Ref	Expression
1		19.31.1	. . 3
2	1	19.32 1967	. 2
3		orcom 387	. . 3
4	3	albii 1640	. 2
5		orcom 387	. 2
6	2, 4, 5	3bitr4i 277	1

Syntax hints:  <->wb 184  \/wo 368  A.wal 1393  F/wnf 1616

This theorem is referenced by:  2eu3  2379

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-12 1854

This theorem depends on definitions:  df-bi 185  df-or 370  df-ex 1613  df-nf 1617