Metamath Proof Explorer
		
		
		
		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  ⊊  Mgm | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sgrpmgm | ⊢ ( 𝑥  ∈  Smgrp  →  𝑥  ∈  Mgm ) | 
						
							| 2 | 1 | ssriv | ⊢ Smgrp  ⊆  Mgm | 
						
							| 3 |  | mgmnsgrpex | ⊢ ∃ 𝑥  ∈  Mgm 𝑥  ∉  Smgrp | 
						
							| 4 |  | ssexnelpss | ⊢ ( ( Smgrp  ⊆  Mgm  ∧  ∃ 𝑥  ∈  Mgm 𝑥  ∉  Smgrp )  →  Smgrp  ⊊  Mgm ) | 
						
							| 5 | 2 3 4 | mp2an | ⊢ Smgrp  ⊊  Mgm |