Theorem lttri2i

Description: Consequence of trichotomy. (Contributed by NM, 19-Jan-1997)

	Ref	Expression
Hypotheses	lt.1	⊢ 𝐴 ∈ ℝ
	lt.2	⊢ 𝐵 ∈ ℝ
Assertion	lttri2i	⊢ ( 𝐴 ≠ 𝐵 ↔ ( 𝐴 < 𝐵 ∨ 𝐵 < 𝐴 ) )

Proof

Step	Hyp	Ref	Expression
1		lt.1	⊢ 𝐴 ∈ ℝ
2		lt.2	⊢ 𝐵 ∈ ℝ
3		lttri2	⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( 𝐴 ≠ 𝐵 ↔ ( 𝐴 < 𝐵 ∨ 𝐵 < 𝐴 ) ) )
4	1 2 3	mp2an	⊢ ( 𝐴 ≠ 𝐵 ↔ ( 𝐴 < 𝐵 ∨ 𝐵 < 𝐴 ) )