Description: If A is not in the range, it is not in the range of any restriction. (Contributed by Glauco Siliprandi, 17-Aug-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | nelrnres | |- ( -. A e. ran B -> -. A e. ran ( B |` C ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rnresss | |- ran ( B |` C ) C_ ran B |
|
2 | ssnel | |- ( ( ran ( B |` C ) C_ ran B /\ -. A e. ran B ) -> -. A e. ran ( B |` C ) ) |
|
3 | 1 2 | mpan | |- ( -. A e. ran B -> -. A e. ran ( B |` C ) ) |