Description: Closure of square. (Contributed by NM, 10-Aug-1999)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | sqcl | ⊢ ( 𝐴 ∈ ℂ → ( 𝐴 ↑ 2 ) ∈ ℂ ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | sqval | ⊢ ( 𝐴 ∈ ℂ → ( 𝐴 ↑ 2 ) = ( 𝐴 · 𝐴 ) ) | |
| 2 | mulcl | ⊢ ( ( 𝐴 ∈ ℂ ∧ 𝐴 ∈ ℂ ) → ( 𝐴 · 𝐴 ) ∈ ℂ ) | |
| 3 | 2 | anidms | ⊢ ( 𝐴 ∈ ℂ → ( 𝐴 · 𝐴 ) ∈ ℂ ) | 
| 4 | 1 3 | eqeltrd | ⊢ ( 𝐴 ∈ ℂ → ( 𝐴 ↑ 2 ) ∈ ℂ ) |