Step |
Hyp |
Ref |
Expression |
1 |
|
elre0re |
|- ( A e. RR -> 0 e. RR ) |
2 |
|
resubval |
|- ( ( 0 e. RR /\ A e. RR ) -> ( 0 -R A ) = ( iota_ x e. RR ( A + x ) = 0 ) ) |
3 |
1 2
|
mpancom |
|- ( A e. RR -> ( 0 -R A ) = ( iota_ x e. RR ( A + x ) = 0 ) ) |
4 |
3
|
eqeq1d |
|- ( A e. RR -> ( ( 0 -R A ) = B <-> ( iota_ x e. RR ( A + x ) = 0 ) = B ) ) |
5 |
4
|
adantr |
|- ( ( A e. RR /\ B e. RR ) -> ( ( 0 -R A ) = B <-> ( iota_ x e. RR ( A + x ) = 0 ) = B ) ) |
6 |
|
renegeu |
|- ( A e. RR -> E! x e. RR ( A + x ) = 0 ) |
7 |
|
oveq2 |
|- ( x = B -> ( A + x ) = ( A + B ) ) |
8 |
7
|
eqeq1d |
|- ( x = B -> ( ( A + x ) = 0 <-> ( A + B ) = 0 ) ) |
9 |
8
|
riota2 |
|- ( ( B e. RR /\ E! x e. RR ( A + x ) = 0 ) -> ( ( A + B ) = 0 <-> ( iota_ x e. RR ( A + x ) = 0 ) = B ) ) |
10 |
6 9
|
sylan2 |
|- ( ( B e. RR /\ A e. RR ) -> ( ( A + B ) = 0 <-> ( iota_ x e. RR ( A + x ) = 0 ) = B ) ) |
11 |
10
|
ancoms |
|- ( ( A e. RR /\ B e. RR ) -> ( ( A + B ) = 0 <-> ( iota_ x e. RR ( A + x ) = 0 ) = B ) ) |
12 |
5 11
|
bitr4d |
|- ( ( A e. RR /\ B e. RR ) -> ( ( 0 -R A ) = B <-> ( A + B ) = 0 ) ) |