Metamath Proof Explorer


Theorem bnj982

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

Ref Expression
Hypotheses bnj982.1 ⊢ φ → ∀ x φ
bnj982.2 ⊢ ψ → ∀ x ψ
bnj982.3 ⊢ χ → ∀ x χ
bnj982.4 ⊢ θ → ∀ x θ
Assertion bnj982 ⊢ φ ∧ ψ ∧ χ ∧ θ → ∀ x φ ∧ ψ ∧ χ ∧ θ

Proof

Step Hyp Ref Expression
1 bnj982.1 ⊢ φ → ∀ x φ
2 bnj982.2 ⊢ ψ → ∀ x ψ
3 bnj982.3 ⊢ χ → ∀ x χ
4 bnj982.4 ⊢ θ → ∀ x θ
5 df-bnj17 ⊢ φ ∧ ψ ∧ χ ∧ θ ↔ φ ∧ ψ ∧ χ ∧ θ
6 1 2 3 hb3an ⊢ φ ∧ ψ ∧ χ → ∀ x φ ∧ ψ ∧ χ
7 6 4 hban ⊢ φ ∧ ψ ∧ χ ∧ θ → ∀ x φ ∧ ψ ∧ χ ∧ θ
8 5 7 hbxfrbi ⊢ φ ∧ ψ ∧ χ ∧ θ → ∀ x φ ∧ ψ ∧ χ ∧ θ