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Description: Positive real closure of the complex power function. (Contributed by Mario Carneiro, 30-May-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | recxpcld.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| recxpcld.2 | ⊢ ( 𝜑 → 0 ≤ 𝐴 ) | ||
| recxpcld.3 | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | ||
| Assertion | recxpcld | ⊢ ( 𝜑 → ( 𝐴 ↑𝑐 𝐵 ) ∈ ℝ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | recxpcld.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| 2 | recxpcld.2 | ⊢ ( 𝜑 → 0 ≤ 𝐴 ) | |
| 3 | recxpcld.3 | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | |
| 4 | recxpcl | ⊢ ( ( 𝐴 ∈ ℝ ∧ 0 ≤ 𝐴 ∧ 𝐵 ∈ ℝ ) → ( 𝐴 ↑𝑐 𝐵 ) ∈ ℝ ) | |
| 5 | 1 2 3 4 | syl3anc | ⊢ ( 𝜑 → ( 𝐴 ↑𝑐 𝐵 ) ∈ ℝ ) |