Theorem recseq

Description: Equality theorem for recs . (Contributed by Stefan O'Rear, 18-Jan-2015)

	Ref	Expression
Assertion	recseq	|- ( F = G -> recs ( F ) = recs ( G ) )

Proof

Step	Hyp	Ref	Expression
1		wrecseq3	|- ( F = G -> wrecs ( _E , On , F ) = wrecs ( _E , On , G ) )
2		df-recs	|- recs ( F ) = wrecs ( _E , On , F )
3		df-recs	|- recs ( G ) = wrecs ( _E , On , G )
4	1 2 3	3eqtr4g	|- ( F = G -> recs ( F ) = recs ( G ) )