Metamath Proof Explorer
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 ) |
Proof
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 ) |