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 e. CC |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-5 | |- 5 = ( 4 + 1 ) |
|
2 | 4cn | |- 4 e. CC |
|
3 | ax-1cn | |- 1 e. CC |
|
4 | 2 3 | addcli | |- ( 4 + 1 ) e. CC |
5 | 1 4 | eqeltri | |- 5 e. CC |