Theorem ornldOLD 899

Description: Obsolete proof of ornld 898 as of 19-Jan-2020. (Contributed by AV, 6-Sep-2018.) (Proof shortened by AV, 13-Oct-2018.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
ornldOLD

Proof of Theorem ornldOLD

Step	Hyp	Ref	Expression
1		orel1 382	. . . 4
2	1	imim2d 52	. . 3
3	2	impcom 430	. 2
4	3	com12 31	1

Syntax hints:  -.wn 3  ->wi 4  \/wo 368  /\wa 369

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 185  df-or 370  df-an 371