Description: The extension of a permutation, fixing the additional element, is a bijection. (Contributed by AV, 7-Jan-2019)
Ref | Expression | ||
---|---|---|---|
Hypotheses | symgext.s | ||
symgext.e | |||
Assertion | symgextf1o |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | symgext.s | ||
2 | symgext.e | ||
3 | 1 2 | symgextf1 | |
4 | 1 2 | symgextfo | |
5 | df-f1o | ||
6 | 3 4 5 | sylanbrc |