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| Mirrors > Home > ILE Home > Th. List > 0re | GIF version | ||
| Description: 0 is a real number. (Contributed by Eric Schmidt, 21-May-2007.) (Revised by Scott Fenton, 3-Jan-2013.) |
| Ref | Expression |
|---|---|
| 0re | ⊢ 0 ∈ ℝ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 1re 8178 | . 2 ⊢ 1 ∈ ℝ | |
| 2 | ax-rnegex 8141 | . 2 ⊢ (1 ∈ ℝ → ∃𝑥 ∈ ℝ (1 + 𝑥) = 0) | |
| 3 | readdcl 8158 | . . . . 5 ⊢ ((1 ∈ ℝ ∧ 𝑥 ∈ ℝ) → (1 + 𝑥) ∈ ℝ) | |
| 4 | 1, 3 | mpan 424 | . . . 4 ⊢ (𝑥 ∈ ℝ → (1 + 𝑥) ∈ ℝ) |
| 5 | eleq1 2294 | . . . 4 ⊢ ((1 + 𝑥) = 0 → ((1 + 𝑥) ∈ ℝ ↔ 0 ∈ ℝ)) | |
| 6 | 4, 5 | syl5ibcom 155 | . . 3 ⊢ (𝑥 ∈ ℝ → ((1 + 𝑥) = 0 → 0 ∈ ℝ)) |
| 7 | 6 | rexlimiv 2644 | . 2 ⊢ (∃𝑥 ∈ ℝ (1 + 𝑥) = 0 → 0 ∈ ℝ) |
| 8 | 1, 2, 7 | mp2b 8 | 1 ⊢ 0 ∈ ℝ |
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