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Description: The image of an abelian group G under a group homomorphism F is an abelian group. (Contributed by Mario Carneiro, 12-May-2014) (Revised by Thierry Arnoux, 26-Jan-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ghmabl.x | ⊢ 𝑋 = ( Base ‘ 𝐺 ) | |
| ghmabl.y | ⊢ 𝑌 = ( Base ‘ 𝐻 ) | ||
| ghmabl.p | ⊢ + = ( +g ‘ 𝐺 ) | ||
| ghmabl.q | ⊢ ⨣ = ( +g ‘ 𝐻 ) | ||
| ghmabl.f | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋 ) → ( 𝐹 ‘ ( 𝑥 + 𝑦 ) ) = ( ( 𝐹 ‘ 𝑥 ) ⨣ ( 𝐹 ‘ 𝑦 ) ) ) | ||
| ghmabl.1 | ⊢ ( 𝜑 → 𝐹 : 𝑋 –onto→ 𝑌 ) | ||
| ghmabl.3 | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | ||
| Assertion | ghmabl | ⊢ ( 𝜑 → 𝐻 ∈ Abel ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ghmabl.x | ⊢ 𝑋 = ( Base ‘ 𝐺 ) | |
| 2 | ghmabl.y | ⊢ 𝑌 = ( Base ‘ 𝐻 ) | |
| 3 | ghmabl.p | ⊢ + = ( +g ‘ 𝐺 ) | |
| 4 | ghmabl.q | ⊢ ⨣ = ( +g ‘ 𝐻 ) | |
| 5 | ghmabl.f | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋 ) → ( 𝐹 ‘ ( 𝑥 + 𝑦 ) ) = ( ( 𝐹 ‘ 𝑥 ) ⨣ ( 𝐹 ‘ 𝑦 ) ) ) | |
| 6 | ghmabl.1 | ⊢ ( 𝜑 → 𝐹 : 𝑋 –onto→ 𝑌 ) | |
| 7 | ghmabl.3 | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | |
| 8 | ablgrp | ⊢ ( 𝐺 ∈ Abel → 𝐺 ∈ Grp ) | |
| 9 | 7 8 | syl | ⊢ ( 𝜑 → 𝐺 ∈ Grp ) |
| 10 | 5 1 2 3 4 6 9 | ghmgrp | ⊢ ( 𝜑 → 𝐻 ∈ Grp ) |
| 11 | ablcmn | ⊢ ( 𝐺 ∈ Abel → 𝐺 ∈ CMnd ) | |
| 12 | 7 11 | syl | ⊢ ( 𝜑 → 𝐺 ∈ CMnd ) |
| 13 | 1 2 3 4 5 6 12 | ghmcmn | ⊢ ( 𝜑 → 𝐻 ∈ CMnd ) |
| 14 | isabl | ⊢ ( 𝐻 ∈ Abel ↔ ( 𝐻 ∈ Grp ∧ 𝐻 ∈ CMnd ) ) | |
| 15 | 10 13 14 | sylanbrc | ⊢ ( 𝜑 → 𝐻 ∈ Abel ) |