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Description: A unit of a sub-division-ring is a nonzero element of the subring. (Contributed by SN, 19-Feb-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sdrgunit.s | |- S = ( R |`s A ) |
|
| sdrgunit.0 | |- .0. = ( 0g ` R ) |
||
| sdrgunit.u | |- U = ( Unit ` S ) |
||
| Assertion | sdrgunit | |- ( A e. ( SubDRing ` R ) -> ( X e. U <-> ( X e. A /\ X =/= .0. ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sdrgunit.s | |- S = ( R |`s A ) |
|
| 2 | sdrgunit.0 | |- .0. = ( 0g ` R ) |
|
| 3 | sdrgunit.u | |- U = ( Unit ` S ) |
|
| 4 | 1 | sdrgdrng | |- ( A e. ( SubDRing ` R ) -> S e. DivRing ) |
| 5 | eqid | |- ( Base ` S ) = ( Base ` S ) |
|
| 6 | eqid | |- ( 0g ` S ) = ( 0g ` S ) |
|
| 7 | 5 3 6 | drngunit | |- ( S e. DivRing -> ( X e. U <-> ( X e. ( Base ` S ) /\ X =/= ( 0g ` S ) ) ) ) |
| 8 | 4 7 | syl | |- ( A e. ( SubDRing ` R ) -> ( X e. U <-> ( X e. ( Base ` S ) /\ X =/= ( 0g ` S ) ) ) ) |
| 9 | 1 | sdrgbas | |- ( A e. ( SubDRing ` R ) -> A = ( Base ` S ) ) |
| 10 | 9 | eleq2d | |- ( A e. ( SubDRing ` R ) -> ( X e. A <-> X e. ( Base ` S ) ) ) |
| 11 | sdrgsubrg | |- ( A e. ( SubDRing ` R ) -> A e. ( SubRing ` R ) ) |
|
| 12 | 1 2 | subrg0 | |- ( A e. ( SubRing ` R ) -> .0. = ( 0g ` S ) ) |
| 13 | 11 12 | syl | |- ( A e. ( SubDRing ` R ) -> .0. = ( 0g ` S ) ) |
| 14 | 13 | neeq2d | |- ( A e. ( SubDRing ` R ) -> ( X =/= .0. <-> X =/= ( 0g ` S ) ) ) |
| 15 | 10 14 | anbi12d | |- ( A e. ( SubDRing ` R ) -> ( ( X e. A /\ X =/= .0. ) <-> ( X e. ( Base ` S ) /\ X =/= ( 0g ` S ) ) ) ) |
| 16 | 8 15 | bitr4d | |- ( A e. ( SubDRing ` R ) -> ( X e. U <-> ( X e. A /\ X =/= .0. ) ) ) |