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Description: Being a unit is a symmetric property, so it transfers to the opposite ring. (Contributed by Mario Carneiro, 4-Dec-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | opprunit.1 | |- U = ( Unit ` R ) |
|
| opprunit.2 | |- S = ( oppR ` R ) |
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| Assertion | opprunit | |- U = ( Unit ` S ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | opprunit.1 | |- U = ( Unit ` R ) |
|
| 2 | opprunit.2 | |- S = ( oppR ` R ) |
|
| 3 | eqid | |- ( Base ` R ) = ( Base ` R ) |
|
| 4 | 2 3 | opprbas | |- ( Base ` R ) = ( Base ` S ) |
| 5 | eqid | |- ( .r ` S ) = ( .r ` S ) |
|
| 6 | eqid | |- ( oppR ` S ) = ( oppR ` S ) |
|
| 7 | eqid | |- ( .r ` ( oppR ` S ) ) = ( .r ` ( oppR ` S ) ) |
|
| 8 | 4 5 6 7 | opprmul | |- ( y ( .r ` ( oppR ` S ) ) x ) = ( x ( .r ` S ) y ) |
| 9 | eqid | |- ( .r ` R ) = ( .r ` R ) |
|
| 10 | 3 9 2 5 | opprmul | |- ( x ( .r ` S ) y ) = ( y ( .r ` R ) x ) |
| 11 | 8 10 | eqtr2i | |- ( y ( .r ` R ) x ) = ( y ( .r ` ( oppR ` S ) ) x ) |
| 12 | 11 | eqeq1i | |- ( ( y ( .r ` R ) x ) = ( 1r ` R ) <-> ( y ( .r ` ( oppR ` S ) ) x ) = ( 1r ` R ) ) |
| 13 | 12 | rexbii | |- ( E. y e. ( Base ` R ) ( y ( .r ` R ) x ) = ( 1r ` R ) <-> E. y e. ( Base ` R ) ( y ( .r ` ( oppR ` S ) ) x ) = ( 1r ` R ) ) |
| 14 | 13 | anbi2i | |- ( ( x e. ( Base ` R ) /\ E. y e. ( Base ` R ) ( y ( .r ` R ) x ) = ( 1r ` R ) ) <-> ( x e. ( Base ` R ) /\ E. y e. ( Base ` R ) ( y ( .r ` ( oppR ` S ) ) x ) = ( 1r ` R ) ) ) |
| 15 | eqid | |- ( ||r ` R ) = ( ||r ` R ) |
|
| 16 | 3 15 9 | dvdsr | |- ( x ( ||r ` R ) ( 1r ` R ) <-> ( x e. ( Base ` R ) /\ E. y e. ( Base ` R ) ( y ( .r ` R ) x ) = ( 1r ` R ) ) ) |
| 17 | 6 4 | opprbas | |- ( Base ` R ) = ( Base ` ( oppR ` S ) ) |
| 18 | eqid | |- ( ||r ` ( oppR ` S ) ) = ( ||r ` ( oppR ` S ) ) |
|
| 19 | 17 18 7 | dvdsr | |- ( x ( ||r ` ( oppR ` S ) ) ( 1r ` R ) <-> ( x e. ( Base ` R ) /\ E. y e. ( Base ` R ) ( y ( .r ` ( oppR ` S ) ) x ) = ( 1r ` R ) ) ) |
| 20 | 14 16 19 | 3bitr4i | |- ( x ( ||r ` R ) ( 1r ` R ) <-> x ( ||r ` ( oppR ` S ) ) ( 1r ` R ) ) |
| 21 | 20 | anbi2ci | |- ( ( x ( ||r ` R ) ( 1r ` R ) /\ x ( ||r ` S ) ( 1r ` R ) ) <-> ( x ( ||r ` S ) ( 1r ` R ) /\ x ( ||r ` ( oppR ` S ) ) ( 1r ` R ) ) ) |
| 22 | eqid | |- ( 1r ` R ) = ( 1r ` R ) |
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| 23 | eqid | |- ( ||r ` S ) = ( ||r ` S ) |
|
| 24 | 1 22 15 2 23 | isunit | |- ( x e. U <-> ( x ( ||r ` R ) ( 1r ` R ) /\ x ( ||r ` S ) ( 1r ` R ) ) ) |
| 25 | eqid | |- ( Unit ` S ) = ( Unit ` S ) |
|
| 26 | 2 22 | oppr1 | |- ( 1r ` R ) = ( 1r ` S ) |
| 27 | 25 26 23 6 18 | isunit | |- ( x e. ( Unit ` S ) <-> ( x ( ||r ` S ) ( 1r ` R ) /\ x ( ||r ` ( oppR ` S ) ) ( 1r ` R ) ) ) |
| 28 | 21 24 27 | 3bitr4i | |- ( x e. U <-> x e. ( Unit ` S ) ) |
| 29 | 28 | eqriv | |- U = ( Unit ` S ) |