Description: The class of all semigroups is a proper subclass of the class of all magmas. (Contributed by AV, 29-Jan-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | sgrpssmgm | |- Smgrp C. Mgm | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | sgrpmgm | |- ( x e. Smgrp -> x e. Mgm ) | |
| 2 | 1 | ssriv | |- Smgrp C_ Mgm | 
| 3 | mgmnsgrpex | |- E. x e. Mgm x e/ Smgrp | |
| 4 | ssexnelpss | |- ( ( Smgrp C_ Mgm /\ E. x e. Mgm x e/ Smgrp ) -> Smgrp C. Mgm ) | |
| 5 | 2 3 4 | mp2an | |- Smgrp C. Mgm |