Theorem dalemqrprot

Description: Lemma for dath . Frequently-used utility lemma. (Contributed by NM, 13-Aug-2012)

	Ref	Expression
Hypotheses	dalema.ph	⊢ ( 𝜑 ↔ ( ( ( 𝐾 ∈ HL ∧ 𝐶 ∈ ( Base ‘ 𝐾 ) ) ∧ ( 𝑃 ∈ 𝐴 ∧ 𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ) ∧ ( 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ∧ 𝑈 ∈ 𝐴 ) ) ∧ ( 𝑌 ∈ 𝑂 ∧ 𝑍 ∈ 𝑂 ) ∧ ( ( ¬ 𝐶 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝐶 ≤ ( 𝑄 ∨ 𝑅 ) ∧ ¬ 𝐶 ≤ ( 𝑅 ∨ 𝑃 ) ) ∧ ( ¬ 𝐶 ≤ ( 𝑆 ∨ 𝑇 ) ∧ ¬ 𝐶 ≤ ( 𝑇 ∨ 𝑈 ) ∧ ¬ 𝐶 ≤ ( 𝑈 ∨ 𝑆 ) ) ∧ ( 𝐶 ≤ ( 𝑃 ∨ 𝑆 ) ∧ 𝐶 ≤ ( 𝑄 ∨ 𝑇 ) ∧ 𝐶 ≤ ( 𝑅 ∨ 𝑈 ) ) ) ) )
	dalemb.j	⊢ ∨ = ( join ‘ 𝐾 )
	dalemb.a	⊢ 𝐴 = ( Atoms ‘ 𝐾 )
Assertion	dalemqrprot	⊢ ( 𝜑 → ( ( 𝑄 ∨ 𝑅 ) ∨ 𝑃 ) = ( ( 𝑃 ∨ 𝑄 ) ∨ 𝑅 ) )

Proof

Step	Hyp	Ref	Expression
1		dalema.ph	⊢ ( 𝜑 ↔ ( ( ( 𝐾 ∈ HL ∧ 𝐶 ∈ ( Base ‘ 𝐾 ) ) ∧ ( 𝑃 ∈ 𝐴 ∧ 𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ) ∧ ( 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ∧ 𝑈 ∈ 𝐴 ) ) ∧ ( 𝑌 ∈ 𝑂 ∧ 𝑍 ∈ 𝑂 ) ∧ ( ( ¬ 𝐶 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝐶 ≤ ( 𝑄 ∨ 𝑅 ) ∧ ¬ 𝐶 ≤ ( 𝑅 ∨ 𝑃 ) ) ∧ ( ¬ 𝐶 ≤ ( 𝑆 ∨ 𝑇 ) ∧ ¬ 𝐶 ≤ ( 𝑇 ∨ 𝑈 ) ∧ ¬ 𝐶 ≤ ( 𝑈 ∨ 𝑆 ) ) ∧ ( 𝐶 ≤ ( 𝑃 ∨ 𝑆 ) ∧ 𝐶 ≤ ( 𝑄 ∨ 𝑇 ) ∧ 𝐶 ≤ ( 𝑅 ∨ 𝑈 ) ) ) ) )
2		dalemb.j	⊢ ∨ = ( join ‘ 𝐾 )
3		dalemb.a	⊢ 𝐴 = ( Atoms ‘ 𝐾 )
4	1	dalemkehl	⊢ ( 𝜑 → 𝐾 ∈ HL )
5	1	dalemqea	⊢ ( 𝜑 → 𝑄 ∈ 𝐴 )
6	1	dalemrea	⊢ ( 𝜑 → 𝑅 ∈ 𝐴 )
7	1	dalempea	⊢ ( 𝜑 → 𝑃 ∈ 𝐴 )
8	2 3	hlatjrot	⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑃 ∈ 𝐴 ) ) → ( ( 𝑄 ∨ 𝑅 ) ∨ 𝑃 ) = ( ( 𝑃 ∨ 𝑄 ) ∨ 𝑅 ) )
9	4 5 6 7 8	syl13anc	⊢ ( 𝜑 → ( ( 𝑄 ∨ 𝑅 ) ∨ 𝑃 ) = ( ( 𝑃 ∨ 𝑄 ) ∨ 𝑅 ) )