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Description: The indexed supremum of a nonempty set of reals, is real if and only if it is bounded-above . (Contributed by Glauco Siliprandi, 23-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | supxrre3rnmpt.x | ⊢ Ⅎ 𝑥 𝜑 | |
| supxrre3rnmpt.a | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | ||
| supxrre3rnmpt.b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 ∈ ℝ ) | ||
| Assertion | supxrre3rnmpt | ⊢ ( 𝜑 → ( sup ( ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) , ℝ* , < ) ∈ ℝ ↔ ∃ 𝑦 ∈ ℝ ∀ 𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | supxrre3rnmpt.x | ⊢ Ⅎ 𝑥 𝜑 | |
| 2 | supxrre3rnmpt.a | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | |
| 3 | supxrre3rnmpt.b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 ∈ ℝ ) | |
| 4 | eqid | ⊢ ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) = ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) | |
| 5 | 1 4 3 | rnmptssd | ⊢ ( 𝜑 → ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ⊆ ℝ ) |
| 6 | 1 3 4 2 | rnmptn0 | ⊢ ( 𝜑 → ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ≠ ∅ ) |
| 7 | supxrre3 | ⊢ ( ( ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ⊆ ℝ ∧ ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ≠ ∅ ) → ( sup ( ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) , ℝ* , < ) ∈ ℝ ↔ ∃ 𝑦 ∈ ℝ ∀ 𝑧 ∈ ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) 𝑧 ≤ 𝑦 ) ) | |
| 8 | 5 6 7 | syl2anc | ⊢ ( 𝜑 → ( sup ( ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) , ℝ* , < ) ∈ ℝ ↔ ∃ 𝑦 ∈ ℝ ∀ 𝑧 ∈ ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) 𝑧 ≤ 𝑦 ) ) |
| 9 | 1 3 | rnmptbd | ⊢ ( 𝜑 → ( ∃ 𝑦 ∈ ℝ ∀ 𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ↔ ∃ 𝑦 ∈ ℝ ∀ 𝑧 ∈ ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) 𝑧 ≤ 𝑦 ) ) |
| 10 | 8 9 | bitr4d | ⊢ ( 𝜑 → ( sup ( ran ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) , ℝ* , < ) ∈ ℝ ↔ ∃ 𝑦 ∈ ℝ ∀ 𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ) ) |