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Description: All subgroups in an abelian group commute. (Contributed by Mario Carneiro, 19-Apr-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ablcntzd.z | ⊢ 𝑍 = ( Cntz ‘ 𝐺 ) | |
| ablcntzd.a | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | ||
| ablcntzd.t | ⊢ ( 𝜑 → 𝑇 ∈ ( SubGrp ‘ 𝐺 ) ) | ||
| ablcntzd.u | ⊢ ( 𝜑 → 𝑈 ∈ ( SubGrp ‘ 𝐺 ) ) | ||
| Assertion | ablcntzd | ⊢ ( 𝜑 → 𝑇 ⊆ ( 𝑍 ‘ 𝑈 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ablcntzd.z | ⊢ 𝑍 = ( Cntz ‘ 𝐺 ) | |
| 2 | ablcntzd.a | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | |
| 3 | ablcntzd.t | ⊢ ( 𝜑 → 𝑇 ∈ ( SubGrp ‘ 𝐺 ) ) | |
| 4 | ablcntzd.u | ⊢ ( 𝜑 → 𝑈 ∈ ( SubGrp ‘ 𝐺 ) ) | |
| 5 | eqid | ⊢ ( Base ‘ 𝐺 ) = ( Base ‘ 𝐺 ) | |
| 6 | 5 | subgss | ⊢ ( 𝑇 ∈ ( SubGrp ‘ 𝐺 ) → 𝑇 ⊆ ( Base ‘ 𝐺 ) ) |
| 7 | 3 6 | syl | ⊢ ( 𝜑 → 𝑇 ⊆ ( Base ‘ 𝐺 ) ) |
| 8 | ablcmn | ⊢ ( 𝐺 ∈ Abel → 𝐺 ∈ CMnd ) | |
| 9 | 2 8 | syl | ⊢ ( 𝜑 → 𝐺 ∈ CMnd ) |
| 10 | 5 | subgss | ⊢ ( 𝑈 ∈ ( SubGrp ‘ 𝐺 ) → 𝑈 ⊆ ( Base ‘ 𝐺 ) ) |
| 11 | 4 10 | syl | ⊢ ( 𝜑 → 𝑈 ⊆ ( Base ‘ 𝐺 ) ) |
| 12 | 5 1 | cntzcmn | ⊢ ( ( 𝐺 ∈ CMnd ∧ 𝑈 ⊆ ( Base ‘ 𝐺 ) ) → ( 𝑍 ‘ 𝑈 ) = ( Base ‘ 𝐺 ) ) |
| 13 | 9 11 12 | syl2anc | ⊢ ( 𝜑 → ( 𝑍 ‘ 𝑈 ) = ( Base ‘ 𝐺 ) ) |
| 14 | 7 13 | sseqtrrd | ⊢ ( 𝜑 → 𝑇 ⊆ ( 𝑍 ‘ 𝑈 ) ) |