Description: suprcld without ax-mulcom , proven trivially from sn-sup3d . (Contributed by SN, 29-Jun-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sn-sup3d.1 | ⊢ ( 𝜑 → 𝐴 ⊆ ℝ ) | |
| sn-sup3d.2 | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | ||
| sn-sup3d.3 | ⊢ ( 𝜑 → ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑦 ≤ 𝑥 ) | ||
| Assertion | sn-suprcld | ⊢ ( 𝜑 → sup ( 𝐴 , ℝ , < ) ∈ ℝ ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | sn-sup3d.1 | ⊢ ( 𝜑 → 𝐴 ⊆ ℝ ) | |
| 2 | sn-sup3d.2 | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | |
| 3 | sn-sup3d.3 | ⊢ ( 𝜑 → ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑦 ≤ 𝑥 ) | |
| 4 | ltso | ⊢ < Or ℝ | |
| 5 | 4 | a1i | ⊢ ( 𝜑 → < Or ℝ ) | 
| 6 | 1 2 3 | sn-sup3d | ⊢ ( 𝜑 → ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 < 𝑦 ∧ ∀ 𝑦 ∈ ℝ ( 𝑦 < 𝑥 → ∃ 𝑧 ∈ 𝐴 𝑦 < 𝑧 ) ) ) | 
| 7 | 5 6 | supcl | ⊢ ( 𝜑 → sup ( 𝐴 , ℝ , < ) ∈ ℝ ) |