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Description: A semiring element plus itself is two times the element. "Two" in an arbitrary (unital) semiring is the sum of the unity element with itself. (Contributed by AV, 24-Aug-2021) Variant of o2timesd for semirings. (Revised by AV, 1-Feb-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | srgo2times.b | |- B = ( Base ` R ) |
|
| srgo2times.p | |- .+ = ( +g ` R ) |
||
| srgo2times.t | |- .x. = ( .r ` R ) |
||
| srgo2times.u | |- .1. = ( 1r ` R ) |
||
| Assertion | srgo2times | |- ( ( R e. SRing /\ A e. B ) -> ( A .+ A ) = ( ( .1. .+ .1. ) .x. A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | srgo2times.b | |- B = ( Base ` R ) |
|
| 2 | srgo2times.p | |- .+ = ( +g ` R ) |
|
| 3 | srgo2times.t | |- .x. = ( .r ` R ) |
|
| 4 | srgo2times.u | |- .1. = ( 1r ` R ) |
|
| 5 | 1 2 3 | srgdir | |- ( ( R e. SRing /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x .+ y ) .x. z ) = ( ( x .x. z ) .+ ( y .x. z ) ) ) |
| 6 | 5 | ralrimivvva | |- ( R e. SRing -> A. x e. B A. y e. B A. z e. B ( ( x .+ y ) .x. z ) = ( ( x .x. z ) .+ ( y .x. z ) ) ) |
| 7 | 6 | adantr | |- ( ( R e. SRing /\ A e. B ) -> A. x e. B A. y e. B A. z e. B ( ( x .+ y ) .x. z ) = ( ( x .x. z ) .+ ( y .x. z ) ) ) |
| 8 | 1 4 | srgidcl | |- ( R e. SRing -> .1. e. B ) |
| 9 | 8 | adantr | |- ( ( R e. SRing /\ A e. B ) -> .1. e. B ) |
| 10 | 1 3 4 | srglidm | |- ( ( R e. SRing /\ x e. B ) -> ( .1. .x. x ) = x ) |
| 11 | 10 | ralrimiva | |- ( R e. SRing -> A. x e. B ( .1. .x. x ) = x ) |
| 12 | 11 | adantr | |- ( ( R e. SRing /\ A e. B ) -> A. x e. B ( .1. .x. x ) = x ) |
| 13 | simpr | |- ( ( R e. SRing /\ A e. B ) -> A e. B ) |
|
| 14 | 7 9 12 13 | o2timesd | |- ( ( R e. SRing /\ A e. B ) -> ( A .+ A ) = ( ( .1. .+ .1. ) .x. A ) ) |