Metamath Proof Explorer


Theorem impd

Description: Importation deduction. (Contributed by NM, 31-Mar-1994)

Ref Expression
Hypothesis impd.1 ⊢ φ → ψ → χ → θ
Assertion impd ⊢ φ → ψ ∧ χ → θ

Proof

Step Hyp Ref Expression
1 impd.1 ⊢ φ → ψ → χ → θ
2 1 com3l ⊢ ψ → χ → φ → θ
3 2 imp ⊢ ψ ∧ χ → φ → θ
4 3 com12 ⊢ φ → ψ ∧ χ → θ