Theorem bnj1219

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

	Ref	Expression
Hypotheses	bnj1219.1	|- ( ch <-> ( ph /\ ps /\ ze ) )
	bnj1219.2	|- ( th <-> ( ch /\ ta /\ et ) )
Assertion	bnj1219	|- ( th -> ps )

Proof

Step	Hyp	Ref	Expression
1		bnj1219.1	|- ( ch <-> ( ph /\ ps /\ ze ) )
2		bnj1219.2	|- ( th <-> ( ch /\ ta /\ et ) )
3	1	simp2bi	|- ( ch -> ps )
4	2 3	bnj835	|- ( th -> ps )