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Description: Asemigroup is a set equipped with an everywhere defined internal operation (so, a magma, see df-mgm ), whose operation is associative. Definition in section II.1 of Bruck p. 23, or of an "associative magma" in definition 5 of BourbakiAlg1 p. 4 . (Contributed by FL, 2-Nov-2009) (Revised by AV, 6-Jan-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-sgrp | |- Smgrp = { g e. Mgm | [. ( Base ` g ) / b ]. [. ( +g ` g ) / o ]. A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | csgrp | |- Smgrp |
|
| 1 | vg | |- g |
|
| 2 | cmgm | |- Mgm |
|
| 3 | cbs | |- Base |
|
| 4 | 1 | cv | |- g |
| 5 | 4 3 | cfv | |- ( Base ` g ) |
| 6 | vb | |- b |
|
| 7 | cplusg | |- +g |
|
| 8 | 4 7 | cfv | |- ( +g ` g ) |
| 9 | vo | |- o |
|
| 10 | vx | |- x |
|
| 11 | 6 | cv | |- b |
| 12 | vy | |- y |
|
| 13 | vz | |- z |
|
| 14 | 10 | cv | |- x |
| 15 | 9 | cv | |- o |
| 16 | 12 | cv | |- y |
| 17 | 14 16 15 | co | |- ( x o y ) |
| 18 | 13 | cv | |- z |
| 19 | 17 18 15 | co | |- ( ( x o y ) o z ) |
| 20 | 16 18 15 | co | |- ( y o z ) |
| 21 | 14 20 15 | co | |- ( x o ( y o z ) ) |
| 22 | 19 21 | wceq | |- ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 23 | 22 13 11 | wral | |- A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 24 | 23 12 11 | wral | |- A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 25 | 24 10 11 | wral | |- A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 26 | 25 9 8 | wsbc | |- [. ( +g ` g ) / o ]. A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 27 | 26 6 5 | wsbc | |- [. ( Base ` g ) / b ]. [. ( +g ` g ) / o ]. A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) |
| 28 | 27 1 2 | crab | |- { g e. Mgm | [. ( Base ` g ) / b ]. [. ( +g ` g ) / o ]. A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) } |
| 29 | 0 28 | wceq | |- Smgrp = { g e. Mgm | [. ( Base ` g ) / b ]. [. ( +g ` g ) / o ]. A. x e. b A. y e. b A. z e. b ( ( x o y ) o z ) = ( x o ( y o z ) ) } |