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Description: The group addition operation is a function. (Contributed by Mario Carneiro, 14-Aug-2015) (Proof shortened by AV, 3-Feb-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | mndplusf.1 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| mndplusf.2 | ⊢ ⨣ = ( +𝑓 ‘ 𝐺 ) | ||
| Assertion | mndplusf | ⊢ ( 𝐺 ∈ Mnd → ⨣ : ( 𝐵 × 𝐵 ) ⟶ 𝐵 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mndplusf.1 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| 2 | mndplusf.2 | ⊢ ⨣ = ( +𝑓 ‘ 𝐺 ) | |
| 3 | mndmgm | ⊢ ( 𝐺 ∈ Mnd → 𝐺 ∈ Mgm ) | |
| 4 | 1 2 | mgmplusf | ⊢ ( 𝐺 ∈ Mgm → ⨣ : ( 𝐵 × 𝐵 ) ⟶ 𝐵 ) |
| 5 | 3 4 | syl | ⊢ ( 𝐺 ∈ Mnd → ⨣ : ( 𝐵 × 𝐵 ) ⟶ 𝐵 ) |