Step |
Hyp |
Ref |
Expression |
1 |
|
ismgmid.b |
|- B = ( Base ` G ) |
2 |
|
ismgmid.o |
|- .0. = ( 0g ` G ) |
3 |
|
ismgmid.p |
|- .+ = ( +g ` G ) |
4 |
|
mgmidcl.e |
|- ( ph -> E. e e. B A. x e. B ( ( e .+ x ) = x /\ ( x .+ e ) = x ) ) |
5 |
|
eqid |
|- .0. = .0. |
6 |
1 2 3 4
|
ismgmid |
|- ( ph -> ( ( .0. e. B /\ A. x e. B ( ( .0. .+ x ) = x /\ ( x .+ .0. ) = x ) ) <-> .0. = .0. ) ) |
7 |
5 6
|
mpbiri |
|- ( ph -> ( .0. e. B /\ A. x e. B ( ( .0. .+ x ) = x /\ ( x .+ .0. ) = x ) ) ) |
8 |
7
|
simprd |
|- ( ph -> A. x e. B ( ( .0. .+ x ) = x /\ ( x .+ .0. ) = x ) ) |
9 |
|
oveq2 |
|- ( x = X -> ( .0. .+ x ) = ( .0. .+ X ) ) |
10 |
|
id |
|- ( x = X -> x = X ) |
11 |
9 10
|
eqeq12d |
|- ( x = X -> ( ( .0. .+ x ) = x <-> ( .0. .+ X ) = X ) ) |
12 |
|
oveq1 |
|- ( x = X -> ( x .+ .0. ) = ( X .+ .0. ) ) |
13 |
12 10
|
eqeq12d |
|- ( x = X -> ( ( x .+ .0. ) = x <-> ( X .+ .0. ) = X ) ) |
14 |
11 13
|
anbi12d |
|- ( x = X -> ( ( ( .0. .+ x ) = x /\ ( x .+ .0. ) = x ) <-> ( ( .0. .+ X ) = X /\ ( X .+ .0. ) = X ) ) ) |
15 |
14
|
rspccva |
|- ( ( A. x e. B ( ( .0. .+ x ) = x /\ ( x .+ .0. ) = x ) /\ X e. B ) -> ( ( .0. .+ X ) = X /\ ( X .+ .0. ) = X ) ) |
16 |
8 15
|
sylan |
|- ( ( ph /\ X e. B ) -> ( ( .0. .+ X ) = X /\ ( X .+ .0. ) = X ) ) |