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Mirrors > Home > MPE Home > Th. List > Mathboxes > dford3 | Structured version Visualization version GIF version |
Description: Ordinals are precisely the hereditarily transitive classes. (Contributed by Stefan O'Rear, 28-Oct-2014.) |
Ref | Expression |
---|---|
dford3 | ⊢ (Ord 𝑁 ↔ (Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ordtr 5737 | . . 3 ⊢ (Ord 𝑁 → Tr 𝑁) | |
2 | ordelord 5745 | . . . . 5 ⊢ ((Ord 𝑁 ∧ 𝑥 ∈ 𝑁) → Ord 𝑥) | |
3 | ordtr 5737 | . . . . 5 ⊢ (Ord 𝑥 → Tr 𝑥) | |
4 | 2, 3 | syl 17 | . . . 4 ⊢ ((Ord 𝑁 ∧ 𝑥 ∈ 𝑁) → Tr 𝑥) |
5 | 4 | ralrimiva 2966 | . . 3 ⊢ (Ord 𝑁 → ∀𝑥 ∈ 𝑁 Tr 𝑥) |
6 | 1, 5 | jca 554 | . 2 ⊢ (Ord 𝑁 → (Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥)) |
7 | simpl 473 | . . 3 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → Tr 𝑁) | |
8 | dford3lem1 37593 | . . . . 5 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → ∀𝑎 ∈ 𝑁 (Tr 𝑎 ∧ ∀𝑥 ∈ 𝑎 Tr 𝑥)) | |
9 | dford3lem2 37594 | . . . . . 6 ⊢ ((Tr 𝑎 ∧ ∀𝑥 ∈ 𝑎 Tr 𝑥) → 𝑎 ∈ On) | |
10 | 9 | ralimi 2952 | . . . . 5 ⊢ (∀𝑎 ∈ 𝑁 (Tr 𝑎 ∧ ∀𝑥 ∈ 𝑎 Tr 𝑥) → ∀𝑎 ∈ 𝑁 𝑎 ∈ On) |
11 | 8, 10 | syl 17 | . . . 4 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → ∀𝑎 ∈ 𝑁 𝑎 ∈ On) |
12 | dfss3 3592 | . . . 4 ⊢ (𝑁 ⊆ On ↔ ∀𝑎 ∈ 𝑁 𝑎 ∈ On) | |
13 | 11, 12 | sylibr 224 | . . 3 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → 𝑁 ⊆ On) |
14 | ordon 6982 | . . . 4 ⊢ Ord On | |
15 | 14 | a1i 11 | . . 3 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → Ord On) |
16 | trssord 5740 | . . 3 ⊢ ((Tr 𝑁 ∧ 𝑁 ⊆ On ∧ Ord On) → Ord 𝑁) | |
17 | 7, 13, 15, 16 | syl3anc 1326 | . 2 ⊢ ((Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥) → Ord 𝑁) |
18 | 6, 17 | impbii 199 | 1 ⊢ (Ord 𝑁 ↔ (Tr 𝑁 ∧ ∀𝑥 ∈ 𝑁 Tr 𝑥)) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 196 ∧ wa 384 ∈ wcel 1990 ∀wral 2912 ⊆ wss 3574 Tr wtr 4752 Ord word 5722 Oncon0 5723 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pr 4906 ax-un 6949 ax-reg 8497 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-ral 2917 df-rex 2918 df-rab 2921 df-v 3202 df-sbc 3436 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-br 4654 df-opab 4713 df-tr 4753 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-ord 5726 df-on 5727 df-suc 5729 |
This theorem is referenced by: dford4 37596 |
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