Theorem jao

Description: Disjunction of antecedents. Compare Theorem *3.44 of WhiteheadRussell p. 113. (Contributed by NM, 5-Apr-1994) (Proof shortened by Wolf Lammen, 4-Apr-2013)

	Ref	Expression
Assertion	jao	|- ( ( ph -> ps ) -> ( ( ch -> ps ) -> ( ( ph \/ ch ) -> ps ) ) )

Proof

Step	Hyp	Ref	Expression
1		pm3.44	|- ( ( ( ph -> ps ) /\ ( ch -> ps ) ) -> ( ( ph \/ ch ) -> ps ) )
2	1	ex	|- ( ( ph -> ps ) -> ( ( ch -> ps ) -> ( ( ph \/ ch ) -> ps ) ) )