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Description: Amonoid is a semigroup, which has a two-sided neutral element. Definition 2 in BourbakiAlg1 p. 12. In other words (according to the definition in Lang p. 3), a monoid is a set equipped with an everywhere defined internal operation (see mndcl ), whose operation is associative (see mndass ) and has a two-sided neutral element (see mndid ), see also ismnd . (Contributed by Mario Carneiro, 6-Jan-2015) (Revised by AV, 1-Feb-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-mnd |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cmnd | ||
| 1 | vg | ||
| 2 | csgrp | ||
| 3 | cbs | ||
| 4 | 1 | cv | |
| 5 | 4 3 | cfv | |
| 6 | vb | ||
| 7 | cplusg | ||
| 8 | 4 7 | cfv | |
| 9 | vp | ||
| 10 | ve | ||
| 11 | 6 | cv | |
| 12 | vx | ||
| 13 | 10 | cv | |
| 14 | 9 | cv | |
| 15 | 12 | cv | |
| 16 | 13 15 14 | co | |
| 17 | 16 15 | wceq | |
| 18 | 15 13 14 | co | |
| 19 | 18 15 | wceq | |
| 20 | 17 19 | wa | |
| 21 | 20 12 11 | wral | |
| 22 | 21 10 11 | wrex | |
| 23 | 22 9 8 | wsbc | |
| 24 | 23 6 5 | wsbc | |
| 25 | 24 1 2 | crab | |
| 26 | 0 25 | wceq |