Theorem bj-nntrans 15597

Description: A natural number is a transitive set. (Contributed by BJ, 22-Nov-2019.) (Proof modification is discouraged.)

Assertion

Ref	Expression
bj-nntrans	⊢ (𝐴 ∈ ω → (𝐵 ∈ 𝐴 → 𝐵 ⊆ 𝐴))

Proof of Theorem bj-nntrans

Dummy variables 𝑥 𝑦 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ral0 3552	. . 3 ⊢ ∀𝑥 ∈ ∅ 𝑥 ⊆ ∅
2		df-suc 4406	. . . . . . 7 ⊢ suc 𝑧 = (𝑧 ∪ {𝑧})
3	2	eleq2i 2263	. . . . . 6 ⊢ (𝑥 ∈ suc 𝑧 ↔ 𝑥 ∈ (𝑧 ∪ {𝑧}))
4		elun 3304	. . . . . . 7 ⊢ (𝑥 ∈ (𝑧 ∪ {𝑧}) ↔ (𝑥 ∈ 𝑧 ∨ 𝑥 ∈ {𝑧}))
5		sssucid 4450	. . . . . . . . . 10 ⊢ 𝑧 ⊆ suc 𝑧
6		sstr2 3190	. . . . . . . . . 10 ⊢ (𝑥 ⊆ 𝑧 → (𝑧 ⊆ suc 𝑧 → 𝑥 ⊆ suc 𝑧))
7	5, 6	mpi 15	. . . . . . . . 9 ⊢ (𝑥 ⊆ 𝑧 → 𝑥 ⊆ suc 𝑧)
8	7	imim2i 12	. . . . . . . 8 ⊢ ((𝑥 ∈ 𝑧 → 𝑥 ⊆ 𝑧) → (𝑥 ∈ 𝑧 → 𝑥 ⊆ suc 𝑧))
9		elsni 3640	. . . . . . . . . 10 ⊢ (𝑥 ∈ {𝑧} → 𝑥 = 𝑧)
10	9, 5	eqsstrdi 3235	. . . . . . . . 9 ⊢ (𝑥 ∈ {𝑧} → 𝑥 ⊆ suc 𝑧)
11	10	a1i 9	. . . . . . . 8 ⊢ ((𝑥 ∈ 𝑧 → 𝑥 ⊆ 𝑧) → (𝑥 ∈ {𝑧} → 𝑥 ⊆ suc 𝑧))
12	8, 11	jaod 718	. . . . . . 7 ⊢ ((𝑥 ∈ 𝑧 → 𝑥 ⊆ 𝑧) → ((𝑥 ∈ 𝑧 ∨ 𝑥 ∈ {𝑧}) → 𝑥 ⊆ suc 𝑧))
13	4, 12	biimtrid 152	. . . . . 6 ⊢ ((𝑥 ∈ 𝑧 → 𝑥 ⊆ 𝑧) → (𝑥 ∈ (𝑧 ∪ {𝑧}) → 𝑥 ⊆ suc 𝑧))
14	3, 13	biimtrid 152	. . . . 5 ⊢ ((𝑥 ∈ 𝑧 → 𝑥 ⊆ 𝑧) → (𝑥 ∈ suc 𝑧 → 𝑥 ⊆ suc 𝑧))
15	14	ralimi2 2557	. . . 4 ⊢ (∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧 → ∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧)
16	15	rgenw 2552	. . 3 ⊢ ∀𝑧 ∈ ω (∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧 → ∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧)
17		bdcv 15494	. . . . . 6 ⊢ BOUNDED 𝑦
18	17	bdss 15510	. . . . 5 ⊢ BOUNDED 𝑥 ⊆ 𝑦
19	18	ax-bdal 15464	. . . 4 ⊢ BOUNDED ∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦
20		nfv 1542	. . . 4 ⊢ Ⅎ𝑦∀𝑥 ∈ ∅ 𝑥 ⊆ ∅
21		nfv 1542	. . . 4 ⊢ Ⅎ𝑦∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧
22		nfv 1542	. . . 4 ⊢ Ⅎ𝑦∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧
23		sseq2 3207	. . . . . 6 ⊢ (𝑦 = ∅ → (𝑥 ⊆ 𝑦 ↔ 𝑥 ⊆ ∅))
24	23	raleqbi1dv 2705	. . . . 5 ⊢ (𝑦 = ∅ → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 ↔ ∀𝑥 ∈ ∅ 𝑥 ⊆ ∅))
25	24	biimprd 158	. . . 4 ⊢ (𝑦 = ∅ → (∀𝑥 ∈ ∅ 𝑥 ⊆ ∅ → ∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦))
26		sseq2 3207	. . . . . 6 ⊢ (𝑦 = 𝑧 → (𝑥 ⊆ 𝑦 ↔ 𝑥 ⊆ 𝑧))
27	26	raleqbi1dv 2705	. . . . 5 ⊢ (𝑦 = 𝑧 → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 ↔ ∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧))
28	27	biimpd 144	. . . 4 ⊢ (𝑦 = 𝑧 → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 → ∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧))
29		sseq2 3207	. . . . . 6 ⊢ (𝑦 = suc 𝑧 → (𝑥 ⊆ 𝑦 ↔ 𝑥 ⊆ suc 𝑧))
30	29	raleqbi1dv 2705	. . . . 5 ⊢ (𝑦 = suc 𝑧 → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 ↔ ∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧))
31	30	biimprd 158	. . . 4 ⊢ (𝑦 = suc 𝑧 → (∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧 → ∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦))
32		nfcv 2339	. . . 4 ⊢ Ⅎ𝑦𝐴
33		nfv 1542	. . . 4 ⊢ Ⅎ𝑦∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴
34		sseq2 3207	. . . . . 6 ⊢ (𝑦 = 𝐴 → (𝑥 ⊆ 𝑦 ↔ 𝑥 ⊆ 𝐴))
35	34	raleqbi1dv 2705	. . . . 5 ⊢ (𝑦 = 𝐴 → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 ↔ ∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴))
36	35	biimpd 144	. . . 4 ⊢ (𝑦 = 𝐴 → (∀𝑥 ∈ 𝑦 𝑥 ⊆ 𝑦 → ∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴))
37	19, 20, 21, 22, 25, 28, 31, 32, 33, 36	bj-bdfindisg 15594	. . 3 ⊢ ((∀𝑥 ∈ ∅ 𝑥 ⊆ ∅ ∧ ∀𝑧 ∈ ω (∀𝑥 ∈ 𝑧 𝑥 ⊆ 𝑧 → ∀𝑥 ∈ suc 𝑧𝑥 ⊆ suc 𝑧)) → (𝐴 ∈ ω → ∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴))
38	1, 16, 37	mp2an 426	. 2 ⊢ (𝐴 ∈ ω → ∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴)
39		nfv 1542	. . 3 ⊢ Ⅎ𝑥 𝐵 ⊆ 𝐴
40		sseq1 3206	. . 3 ⊢ (𝑥 = 𝐵 → (𝑥 ⊆ 𝐴 ↔ 𝐵 ⊆ 𝐴))
41	39, 40	rspc 2862	. 2 ⊢ (𝐵 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 𝑥 ⊆ 𝐴 → 𝐵 ⊆ 𝐴))
42	38, 41	syl5com 29	1 ⊢ (𝐴 ∈ ω → (𝐵 ∈ 𝐴 → 𝐵 ⊆ 𝐴))

Syntax hints:   → wi 4   ∨ wo 709   = wceq 1364   ∈ wcel 2167  ∀wral 2475   ∪ cun 3155   ⊆ wss 3157  ∅c0 3450  {csn 3622  suc csuc 4400  ωcom 4626

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 710  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-10 1519  ax-11 1520  ax-i12 1521  ax-bndl 1523  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-13 2169  ax-14 2170  ax-ext 2178  ax-nul 4159  ax-pr 4242  ax-un 4468  ax-bd0 15459  ax-bdor 15462  ax-bdal 15464  ax-bdex 15465  ax-bdeq 15466  ax-bdel 15467  ax-bdsb 15468  ax-bdsep 15530  ax-infvn 15587

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1475  df-sb 1777  df-clab 2183  df-cleq 2189  df-clel 2192  df-nfc 2328  df-ral 2480  df-rex 2481  df-rab 2484  df-v 2765  df-dif 3159  df-un 3161  df-in 3163  df-ss 3170  df-nul 3451  df-sn 3628  df-pr 3629  df-uni 3840  df-int 3875  df-suc 4406  df-iom 4627  df-bdc 15487  df-bj-ind 15573

This theorem is referenced by:  bj-nntrans2  15598  bj-nnelirr  15599  bj-nnen2lp  15600