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 ) |