Theorem freq2 5085

Description: Equality theorem for the well-founded predicate. (Contributed by NM, 3-Apr-1994.)

Assertion

Ref	Expression
freq2	|- ( A = B -> ( R Fr A <-> R Fr B ) )

Proof of Theorem freq2

Step	Hyp	Ref	Expression
1		eqimss2 3658	. . 3 |- ( A = B -> B C_ A )
2		frss 5081	. . 3 |- ( B C_ A -> ( R Fr A -> R Fr B ) )
3	1, 2	syl 17	. 2 |- ( A = B -> ( R Fr A -> R Fr B ) )
4		eqimss 3657	. . 3 |- ( A = B -> A C_ B )
5		frss 5081	. . 3 |- ( A C_ B -> ( R Fr B -> R Fr A ) )
6	4, 5	syl 17	. 2 |- ( A = B -> ( R Fr B -> R Fr A ) )
7	3, 6	impbid 202	1 |- ( A = B -> ( R Fr A <-> R Fr B ) )

Syntax hints:   -> wi 4   <-> wb 196   = wceq 1483   C_ wss 3574   Fr wfr 5070

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-in 3581  df-ss 3588  df-fr 5073

This theorem is referenced by:  weeq2  5103  frsn  5189  f1oweALT  7152  frfi  8205  freq12d  37609  ifr0  38654