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Description: Addition of 2 positive numbers is positive. (Contributed by NM, 18-May-1999)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | lt2.1 | ⊢ 𝐴 ∈ ℝ | |
| lt2.2 | ⊢ 𝐵 ∈ ℝ | ||
| addgt0i.3 | ⊢ 0 < 𝐴 | ||
| addgt0i.4 | ⊢ 0 < 𝐵 | ||
| Assertion | addgt0ii | ⊢ 0 < ( 𝐴 + 𝐵 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | lt2.1 | ⊢ 𝐴 ∈ ℝ | |
| 2 | lt2.2 | ⊢ 𝐵 ∈ ℝ | |
| 3 | addgt0i.3 | ⊢ 0 < 𝐴 | |
| 4 | addgt0i.4 | ⊢ 0 < 𝐵 | |
| 5 | 1 2 | addgt0i | ⊢ ( ( 0 < 𝐴 ∧ 0 < 𝐵 ) → 0 < ( 𝐴 + 𝐵 ) ) |
| 6 | 3 4 5 | mp2an | ⊢ 0 < ( 𝐴 + 𝐵 ) |