Description: "Reverse" second Peano postulate analogue for complex numbers: A complex number minus 1 is a complex number. (Contributed by Alexander van der Vekens, 18-Mar-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | peano2cnm | |- ( N e. CC -> ( N - 1 ) e. CC ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax-1cn | |- 1 e. CC |
|
| 2 | subcl | |- ( ( N e. CC /\ 1 e. CC ) -> ( N - 1 ) e. CC ) |
|
| 3 | 1 2 | mpan2 | |- ( N e. CC -> ( N - 1 ) e. CC ) |