Theorem ax1hfs 15718

Description: Heyting's formal system Axiom #1 from [Heyting] p. 127. (Contributed by MM, 11-Aug-2018.)

Assertion

Ref	Expression
ax1hfs	⊢ (𝜑 → (𝜑 ∧ 𝜑))

Proof of Theorem ax1hfs

Step	Hyp	Ref	Expression
1		ax-ia3 108	. 2 ⊢ (𝜑 → (𝜑 → (𝜑 ∧ 𝜑)))
2	1	pm2.43i 49	1 ⊢ (𝜑 → (𝜑 ∧ 𝜑))

Syntax hints:   → wi 4   ∧ wa 104

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia3 108

This theorem is referenced by: (None)