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Metamath Proof Explorer

Theorem isposi

Description: Properties that determine a poset (implicit structure version). (Contributed by NM, 11-Sep-2011)

Ref Expression
Hypotheses isposi.k ⊢ 𝐾 ∈ V
isposi.b ⊢ 𝐵 = ( Base ‘ 𝐾 )
isposi.l ⊢ ≤ = ( le ‘ 𝐾 )
isposi.1 ⊢ ( 𝑥 ∈ 𝐵 → 𝑥 ≤ 𝑥 )
isposi.2 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ) → ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) )
isposi.3 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧 ) → 𝑥 ≤ 𝑧 ) )
Assertion isposi 𝐾 ∈ Poset

Proof

Step Hyp Ref Expression
1 isposi.k ⊢ 𝐾 ∈ V
2 isposi.b ⊢ 𝐵 = ( Base ‘ 𝐾 )
3 isposi.l ⊢ ≤ = ( le ‘ 𝐾 )
4 isposi.1 ⊢ ( 𝑥 ∈ 𝐵 → 𝑥 ≤ 𝑥 )
5 isposi.2 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ) → ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) )
6 isposi.3 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧 ) → 𝑥 ≤ 𝑧 ) )
7 4 3ad2ant1 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → 𝑥 ≤ 𝑥 )
8 5 3adant3 ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) )
9 7 8 6 3jca ⊢ ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → ( 𝑥 ≤ 𝑥 ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧 ) → 𝑥 ≤ 𝑧 ) ) )
10 9 rgen3 ⊢ ∀ 𝑥 ∈ 𝐵 ∀ 𝑦 ∈ 𝐵 ∀ 𝑧 ∈ 𝐵 ( 𝑥 ≤ 𝑥 ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧 ) → 𝑥 ≤ 𝑧 ) )
11 2 3 ispos ⊢ ( 𝐾 ∈ Poset ↔ ( 𝐾 ∈ V ∧ ∀ 𝑥 ∈ 𝐵 ∀ 𝑦 ∈ 𝐵 ∀ 𝑧 ∈ 𝐵 ( 𝑥 ≤ 𝑥 ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥 ) → 𝑥 = 𝑦 ) ∧ ( ( 𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧 ) → 𝑥 ≤ 𝑧 ) ) ) )
12 1 10 11 mpbir2an ⊢ 𝐾 ∈ Poset