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Description: A permutation (element of the symmetric group) is a function from a set into itself. (Contributed by AV, 1-Jan-2019)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | symgbas.1 | ⊢ 𝐺 = ( SymGrp ‘ 𝐴 ) | |
| symgbas.2 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | ||
| Assertion | symgbasf | ⊢ ( 𝐹 ∈ 𝐵 → 𝐹 : 𝐴 ⟶ 𝐴 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | symgbas.1 | ⊢ 𝐺 = ( SymGrp ‘ 𝐴 ) | |
| 2 | symgbas.2 | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| 3 | 1 2 | symgbasf1o | ⊢ ( 𝐹 ∈ 𝐵 → 𝐹 : 𝐴 –1-1-onto→ 𝐴 ) |
| 4 | f1of | ⊢ ( 𝐹 : 𝐴 –1-1-onto→ 𝐴 → 𝐹 : 𝐴 ⟶ 𝐴 ) | |
| 5 | 3 4 | syl | ⊢ ( 𝐹 ∈ 𝐵 → 𝐹 : 𝐴 ⟶ 𝐴 ) |