Theorem mp1i 11

Description: Drop and replace an antecedent. (Contributed by Stefan O'Rear, 29-Jan-2015.)

Hypotheses

Ref	Expression
mp1i.a	⊢ φ
mp1i.b	⊢ (φ → ψ)

Assertion

Ref	Expression
mp1i	⊢ (χ → ψ)

Proof of Theorem mp1i

Step	Hyp	Ref	Expression
1		mp1i.a	. . 3 ⊢ φ
2		mp1i.b	. . 3 ⊢ (φ → ψ)
3	1, 2	ax-mp 5	. 2 ⊢ ψ
4	3	a1i 10	1 ⊢ (χ → ψ)

Syntax hints:   → wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6

This theorem is referenced by: (None)