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Description: A Tarski set is well-orderable. (Contributed by Mario Carneiro, 19-Apr-2013) (Revised by Mario Carneiro, 29-Apr-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | tskwe | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → 𝐴 ∈ dom card ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pwexg | ⊢ ( 𝐴 ∈ 𝑉 → 𝒫 𝐴 ∈ V ) | |
| 2 | rabexg | ⊢ ( 𝒫 𝐴 ∈ V → { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ∈ V ) | |
| 3 | incom | ⊢ ( { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ∩ On ) = ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) | |
| 4 | inex1g | ⊢ ( { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ∈ V → ( { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ∩ On ) ∈ V ) | |
| 5 | 3 4 | eqeltrrid | ⊢ ( { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ∈ V → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ V ) |
| 6 | inss1 | ⊢ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ On | |
| 7 | 6 | sseli | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → 𝑧 ∈ On ) |
| 8 | onelon | ⊢ ( ( 𝑧 ∈ On ∧ 𝑦 ∈ 𝑧 ) → 𝑦 ∈ On ) | |
| 9 | 8 | ancoms | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ On ) → 𝑦 ∈ On ) |
| 10 | 7 9 | sylan2 | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ On ) |
| 11 | onelss | ⊢ ( 𝑧 ∈ On → ( 𝑦 ∈ 𝑧 → 𝑦 ⊆ 𝑧 ) ) | |
| 12 | 11 | impcom | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ On ) → 𝑦 ⊆ 𝑧 ) |
| 13 | 7 12 | sylan2 | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ⊆ 𝑧 ) |
| 14 | inss2 | ⊢ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } | |
| 15 | 14 | sseli | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → 𝑧 ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 16 | breq1 | ⊢ ( 𝑥 = 𝑧 → ( 𝑥 ≺ 𝐴 ↔ 𝑧 ≺ 𝐴 ) ) | |
| 17 | 16 | elrab | ⊢ ( 𝑧 ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ↔ ( 𝑧 ∈ 𝒫 𝐴 ∧ 𝑧 ≺ 𝐴 ) ) |
| 18 | 15 17 | sylib | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → ( 𝑧 ∈ 𝒫 𝐴 ∧ 𝑧 ≺ 𝐴 ) ) |
| 19 | 18 | simpld | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → 𝑧 ∈ 𝒫 𝐴 ) |
| 20 | 19 | elpwid | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → 𝑧 ⊆ 𝐴 ) |
| 21 | 20 | adantl | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑧 ⊆ 𝐴 ) |
| 22 | 13 21 | sstrd | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ⊆ 𝐴 ) |
| 23 | velpw | ⊢ ( 𝑦 ∈ 𝒫 𝐴 ↔ 𝑦 ⊆ 𝐴 ) | |
| 24 | 22 23 | sylibr | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ 𝒫 𝐴 ) |
| 25 | vex | ⊢ 𝑧 ∈ V | |
| 26 | ssdomg | ⊢ ( 𝑧 ∈ V → ( 𝑦 ⊆ 𝑧 → 𝑦 ≼ 𝑧 ) ) | |
| 27 | 25 13 26 | mpsyl | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ≼ 𝑧 ) |
| 28 | 18 | simprd | ⊢ ( 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → 𝑧 ≺ 𝐴 ) |
| 29 | 28 | adantl | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑧 ≺ 𝐴 ) |
| 30 | domsdomtr | ⊢ ( ( 𝑦 ≼ 𝑧 ∧ 𝑧 ≺ 𝐴 ) → 𝑦 ≺ 𝐴 ) | |
| 31 | 27 29 30 | syl2anc | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ≺ 𝐴 ) |
| 32 | breq1 | ⊢ ( 𝑥 = 𝑦 → ( 𝑥 ≺ 𝐴 ↔ 𝑦 ≺ 𝐴 ) ) | |
| 33 | 32 | elrab | ⊢ ( 𝑦 ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ↔ ( 𝑦 ∈ 𝒫 𝐴 ∧ 𝑦 ≺ 𝐴 ) ) |
| 34 | 24 31 33 | sylanbrc | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 35 | 10 34 | elind | ⊢ ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) |
| 36 | 35 | gen2 | ⊢ ∀ 𝑦 ∀ 𝑧 ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) |
| 37 | dftr2 | ⊢ ( Tr ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ↔ ∀ 𝑦 ∀ 𝑧 ( ( 𝑦 ∈ 𝑧 ∧ 𝑧 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) → 𝑦 ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) ) | |
| 38 | 36 37 | mpbir | ⊢ Tr ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 39 | ordon | ⊢ Ord On | |
| 40 | trssord | ⊢ ( ( Tr ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ On ∧ Ord On ) → Ord ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) | |
| 41 | 38 6 39 40 | mp3an | ⊢ Ord ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 42 | elong | ⊢ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ V → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ↔ Ord ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) ) | |
| 43 | 41 42 | mpbiri | ⊢ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ V → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ) |
| 44 | 1 2 5 43 | 4syl | ⊢ ( 𝐴 ∈ 𝑉 → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ) |
| 45 | 44 | adantr | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ) |
| 46 | simpr | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) | |
| 47 | 14 46 | sstrid | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ 𝐴 ) |
| 48 | ssdomg | ⊢ ( 𝐴 ∈ 𝑉 → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ 𝐴 → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≼ 𝐴 ) ) | |
| 49 | 48 | adantr | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ 𝐴 → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≼ 𝐴 ) ) |
| 50 | 47 49 | mpd | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≼ 𝐴 ) |
| 51 | ordirr | ⊢ ( Ord ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → ¬ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) | |
| 52 | 41 51 | mp1i | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ¬ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) |
| 53 | 44 | 3ad2ant1 | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ) |
| 54 | elpw2g | ⊢ ( 𝐴 ∈ 𝑉 → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ 𝒫 𝐴 ↔ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ 𝐴 ) ) | |
| 55 | 54 | adantr | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ 𝒫 𝐴 ↔ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ⊆ 𝐴 ) ) |
| 56 | 47 55 | mpbird | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ 𝒫 𝐴 ) |
| 57 | 56 | 3adant3 | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ 𝒫 𝐴 ) |
| 58 | simp3 | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) | |
| 59 | nfcv | ⊢ Ⅎ 𝑥 On | |
| 60 | nfrab1 | ⊢ Ⅎ 𝑥 { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } | |
| 61 | 59 60 | nfin | ⊢ Ⅎ 𝑥 ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 62 | nfcv | ⊢ Ⅎ 𝑥 𝒫 𝐴 | |
| 63 | nfcv | ⊢ Ⅎ 𝑥 ≺ | |
| 64 | nfcv | ⊢ Ⅎ 𝑥 𝐴 | |
| 65 | 61 63 64 | nfbr | ⊢ Ⅎ 𝑥 ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 |
| 66 | breq1 | ⊢ ( 𝑥 = ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) → ( 𝑥 ≺ 𝐴 ↔ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) ) | |
| 67 | 61 62 65 66 | elrabf | ⊢ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ↔ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ 𝒫 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) ) |
| 68 | 57 58 67 | sylanbrc | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) |
| 69 | 53 68 | elind | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) |
| 70 | 69 | 3expia | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ) ) |
| 71 | 52 70 | mtod | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ¬ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) |
| 72 | bren2 | ⊢ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≈ 𝐴 ↔ ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≼ 𝐴 ∧ ¬ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≺ 𝐴 ) ) | |
| 73 | 50 71 72 | sylanbrc | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≈ 𝐴 ) |
| 74 | isnumi | ⊢ ( ( ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ∈ On ∧ ( On ∩ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ) ≈ 𝐴 ) → 𝐴 ∈ dom card ) | |
| 75 | 45 73 74 | syl2anc | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ { 𝑥 ∈ 𝒫 𝐴 ∣ 𝑥 ≺ 𝐴 } ⊆ 𝐴 ) → 𝐴 ∈ dom card ) |