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Description: Two ways of saying a function is a 1-1-onto mapping of A to itself. (Contributed by Paul Chapman, 25-Feb-2008) (Revised by Mario Carneiro, 28-Jan-2015)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | symgbas.1 | ⊢ 𝐺 = ( SymGrp ‘ 𝐴 ) | |
| symgbas.2 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | ||
| Assertion | elsymgbas | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 ∈ 𝐵 ↔ 𝐹 : 𝐴 –1-1-onto→ 𝐴 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | symgbas.1 | ⊢ 𝐺 = ( SymGrp ‘ 𝐴 ) | |
| 2 | symgbas.2 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| 3 | elex | ⊢ ( 𝐹 ∈ 𝐵 → 𝐹 ∈ V ) | |
| 4 | 3 | a1i | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 ∈ 𝐵 → 𝐹 ∈ V ) ) |
| 5 | f1of | ⊢ ( 𝐹 : 𝐴 –1-1-onto→ 𝐴 → 𝐹 : 𝐴 ⟶ 𝐴 ) | |
| 6 | fex | ⊢ ( ( 𝐹 : 𝐴 ⟶ 𝐴 ∧ 𝐴 ∈ 𝑉 ) → 𝐹 ∈ V ) | |
| 7 | 6 | expcom | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 : 𝐴 ⟶ 𝐴 → 𝐹 ∈ V ) ) |
| 8 | 5 7 | syl5 | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 : 𝐴 –1-1-onto→ 𝐴 → 𝐹 ∈ V ) ) |
| 9 | 1 2 | elsymgbas2 | ⊢ ( 𝐹 ∈ V → ( 𝐹 ∈ 𝐵 ↔ 𝐹 : 𝐴 –1-1-onto→ 𝐴 ) ) |
| 10 | 9 | a1i | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 ∈ V → ( 𝐹 ∈ 𝐵 ↔ 𝐹 : 𝐴 –1-1-onto→ 𝐴 ) ) ) |
| 11 | 4 8 10 | pm5.21ndd | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐹 ∈ 𝐵 ↔ 𝐹 : 𝐴 –1-1-onto→ 𝐴 ) ) |