Description: A semiring is a monoid under multiplication. (Contributed by Thierry Arnoux, 21-Mar-2018)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | srgmgp.g | |- G = ( mulGrp ` R ) | |
| Assertion | srgmgp | |- ( R e. SRing -> G e. Mnd ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | srgmgp.g | |- G = ( mulGrp ` R ) | |
| 2 | eqid | |- ( Base ` R ) = ( Base ` R ) | |
| 3 | eqid | |- ( +g ` R ) = ( +g ` R ) | |
| 4 | eqid | |- ( .r ` R ) = ( .r ` R ) | |
| 5 | eqid | |- ( 0g ` R ) = ( 0g ` R ) | |
| 6 | 2 1 3 4 5 | issrg | |- ( R e. SRing <-> ( R e. CMnd /\ G e. Mnd /\ A. x e. ( Base ` R ) ( A. y e. ( Base ` R ) A. z e. ( Base ` R ) ( ( x ( .r ` R ) ( y ( +g ` R ) z ) ) = ( ( x ( .r ` R ) y ) ( +g ` R ) ( x ( .r ` R ) z ) ) /\ ( ( x ( +g ` R ) y ) ( .r ` R ) z ) = ( ( x ( .r ` R ) z ) ( +g ` R ) ( y ( .r ` R ) z ) ) ) /\ ( ( ( 0g ` R ) ( .r ` R ) x ) = ( 0g ` R ) /\ ( x ( .r ` R ) ( 0g ` R ) ) = ( 0g ` R ) ) ) ) ) | 
| 7 | 6 | simp2bi | |- ( R e. SRing -> G e. Mnd ) |