Description: The image of a restriction is a subset of the original image. (Contributed by Glauco Siliprandi, 23-Oct-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | resimass | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | resss | |
|
2 | imass1 | |
|
3 | 1 2 | ax-mp | |