Theorem issod

Description: An irreflexive, transitive, linear relation is a strict ordering. (Contributed by NM, 21-Jan-1996) (Revised by Mario Carneiro, 9-Jul-2014)

	Ref	Expression
Hypotheses	issod.1	⊢ ( 𝜑 → 𝑅 Po 𝐴 )
	issod.2	⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐴 ) ) → ( 𝑥 𝑅 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 𝑅 𝑥 ) )
Assertion	issod	⊢ ( 𝜑 → 𝑅 Or 𝐴 )

Proof

Step	Hyp	Ref	Expression
1		issod.1	⊢ ( 𝜑 → 𝑅 Po 𝐴 )
2		issod.2	⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐴 ) ) → ( 𝑥 𝑅 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 𝑅 𝑥 ) )
3	2	ralrimivva	⊢ ( 𝜑 → ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ( 𝑥 𝑅 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 𝑅 𝑥 ) )
4		df-so	⊢ ( 𝑅 Or 𝐴 ↔ ( 𝑅 Po 𝐴 ∧ ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ( 𝑥 𝑅 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 𝑅 𝑥 ) ) )
5	1 3 4	sylanbrc	⊢ ( 𝜑 → 𝑅 Or 𝐴 )