Description: Every magma is trivially a submagma of itself. (Contributed by AV, 26-Feb-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | submgmss.b | ⊢ 𝐵 = ( Base ‘ 𝑀 ) | |
| Assertion | submgmid | ⊢ ( 𝑀 ∈ Mgm → 𝐵 ∈ ( SubMgm ‘ 𝑀 ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | submgmss.b | ⊢ 𝐵 = ( Base ‘ 𝑀 ) | |
| 2 | ssidd | ⊢ ( 𝑀 ∈ Mgm → 𝐵 ⊆ 𝐵 ) | |
| 3 | 1 | ressid | ⊢ ( 𝑀 ∈ Mgm → ( 𝑀 ↾s 𝐵 ) = 𝑀 ) | 
| 4 | id | ⊢ ( 𝑀 ∈ Mgm → 𝑀 ∈ Mgm ) | |
| 5 | 3 4 | eqeltrd | ⊢ ( 𝑀 ∈ Mgm → ( 𝑀 ↾s 𝐵 ) ∈ Mgm ) | 
| 6 | eqid | ⊢ ( 𝑀 ↾s 𝐵 ) = ( 𝑀 ↾s 𝐵 ) | |
| 7 | 1 6 | issubmgm2 | ⊢ ( 𝑀 ∈ Mgm → ( 𝐵 ∈ ( SubMgm ‘ 𝑀 ) ↔ ( 𝐵 ⊆ 𝐵 ∧ ( 𝑀 ↾s 𝐵 ) ∈ Mgm ) ) ) | 
| 8 | 2 5 7 | mpbir2and | ⊢ ( 𝑀 ∈ Mgm → 𝐵 ∈ ( SubMgm ‘ 𝑀 ) ) |