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Description: Lemma for ackbij1 . (Contributed by Stefan O'Rear, 18-Nov-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | ackbij.f | ⊢ 𝐹 = ( 𝑥 ∈ ( 𝒫 ω ∩ Fin ) ↦ ( card ‘ ∪ 𝑦 ∈ 𝑥 ( { 𝑦 } × 𝒫 𝑦 ) ) ) | |
| Assertion | ackbij1lem17 | ⊢ 𝐹 : ( 𝒫 ω ∩ Fin ) –1-1→ ω |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ackbij.f | ⊢ 𝐹 = ( 𝑥 ∈ ( 𝒫 ω ∩ Fin ) ↦ ( card ‘ ∪ 𝑦 ∈ 𝑥 ( { 𝑦 } × 𝒫 𝑦 ) ) ) | |
| 2 | 1 | ackbij1lem10 | ⊢ 𝐹 : ( 𝒫 ω ∩ Fin ) ⟶ ω |
| 3 | 1 | ackbij1lem16 | ⊢ ( ( 𝑎 ∈ ( 𝒫 ω ∩ Fin ) ∧ 𝑏 ∈ ( 𝒫 ω ∩ Fin ) ) → ( ( 𝐹 ‘ 𝑎 ) = ( 𝐹 ‘ 𝑏 ) → 𝑎 = 𝑏 ) ) |
| 4 | 3 | rgen2 | ⊢ ∀ 𝑎 ∈ ( 𝒫 ω ∩ Fin ) ∀ 𝑏 ∈ ( 𝒫 ω ∩ Fin ) ( ( 𝐹 ‘ 𝑎 ) = ( 𝐹 ‘ 𝑏 ) → 𝑎 = 𝑏 ) |
| 5 | dff13 | ⊢ ( 𝐹 : ( 𝒫 ω ∩ Fin ) –1-1→ ω ↔ ( 𝐹 : ( 𝒫 ω ∩ Fin ) ⟶ ω ∧ ∀ 𝑎 ∈ ( 𝒫 ω ∩ Fin ) ∀ 𝑏 ∈ ( 𝒫 ω ∩ Fin ) ( ( 𝐹 ‘ 𝑎 ) = ( 𝐹 ‘ 𝑏 ) → 𝑎 = 𝑏 ) ) ) | |
| 6 | 2 4 5 | mpbir2an | ⊢ 𝐹 : ( 𝒫 ω ∩ Fin ) –1-1→ ω |