Description: A complex number times its conjugate is nonnegative. (Contributed by NM, 28-May-1999)
Ref | Expression | ||
---|---|---|---|
Hypothesis | recl.1 | ⊢ 𝐴 ∈ ℂ | |
Assertion | cjmulge0i | ⊢ 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | recl.1 | ⊢ 𝐴 ∈ ℂ | |
2 | cjmulge0 | ⊢ ( 𝐴 ∈ ℂ → 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) ) ) | |
3 | 1 2 | ax-mp | ⊢ 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) ) |