Description: Property of being a manifold. (Contributed by Thierry Arnoux, 28-Dec-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | ismntoplly | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl | |
|
2 | simpl | |
|
3 | 2 | eleq1d | |
4 | simpr | |
|
5 | 4 | eleq1d | |
6 | 4 | eleq1d | |
7 | 2fveq3 | |
|
8 | 7 | eceq1d | |
9 | llyeq | |
|
10 | 8 9 | syl | |
11 | 10 | adantr | |
12 | 4 11 | eleq12d | |
13 | 5 6 12 | 3anbi123d | |
14 | 3 13 | anbi12d | |
15 | df-mntop | |
|
16 | 14 15 | brabga | |
17 | 1 16 | mpbirand | |