Description: The number 5 is a complex number. (Contributed by David A. Wheeler, 8-Dec-2018) Reduce dependencies on axioms. (Revised by Steven Nguyen, 4-Oct-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 5cn | ⊢ 5 ∈ ℂ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-5 | ⊢ 5 = ( 4 + 1 ) | |
| 2 | 4cn | ⊢ 4 ∈ ℂ | |
| 3 | ax-1cn | ⊢ 1 ∈ ℂ | |
| 4 | 2 3 | addcli | ⊢ ( 4 + 1 ) ∈ ℂ |
| 5 | 1 4 | eqeltri | ⊢ 5 ∈ ℂ |