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Description: The group addition operation is a function onto the base set/set of group elements. (Contributed by NM, 30-Oct-2006) (Revised by AV, 30-Aug-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | grpplusf.1 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| grpplusf.2 | ⊢ 𝐹 = ( +𝑓 ‘ 𝐺 ) | ||
| Assertion | grpplusfo | ⊢ ( 𝐺 ∈ Grp → 𝐹 : ( 𝐵 × 𝐵 ) –onto→ 𝐵 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | grpplusf.1 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| 2 | grpplusf.2 | ⊢ 𝐹 = ( +𝑓 ‘ 𝐺 ) | |
| 3 | grpmnd | ⊢ ( 𝐺 ∈ Grp → 𝐺 ∈ Mnd ) | |
| 4 | 1 2 | mndpfo | ⊢ ( 𝐺 ∈ Mnd → 𝐹 : ( 𝐵 × 𝐵 ) –onto→ 𝐵 ) |
| 5 | 3 4 | syl | ⊢ ( 𝐺 ∈ Grp → 𝐹 : ( 𝐵 × 𝐵 ) –onto→ 𝐵 ) |