Theorem domtr 6265

Description: Transitivity of dominance relation. Theorem 17 of [Suppes] p. 94. (Contributed by NM, 4-Jun-1998.) (Revised by Mario Carneiro, 15-Nov-2014.)

Assertion

Ref	Expression
domtr	⊢ ((𝐴 ≼ 𝐵 ∧ 𝐵 ≼ 𝐶) → 𝐴 ≼ 𝐶)

Proof of Theorem domtr

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

Step	Hyp	Ref	Expression
1		reldom 6226	. 2 ⊢ Rel ≼
2		vex 2560	. . . 4 ⊢ 𝑦 ∈ V
3	2	brdom 6231	. . 3 ⊢ (𝑥 ≼ 𝑦 ↔ ∃𝑔 𝑔:𝑥–1-1→𝑦)
4		vex 2560	. . . 4 ⊢ 𝑧 ∈ V
5	4	brdom 6231	. . 3 ⊢ (𝑦 ≼ 𝑧 ↔ ∃𝑓 𝑓:𝑦–1-1→𝑧)
6		eeanv 1807	. . . 4 ⊢ (∃𝑔∃𝑓(𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) ↔ (∃𝑔 𝑔:𝑥–1-1→𝑦 ∧ ∃𝑓 𝑓:𝑦–1-1→𝑧))
7		f1co 5101	. . . . . . . 8 ⊢ ((𝑓:𝑦–1-1→𝑧 ∧ 𝑔:𝑥–1-1→𝑦) → (𝑓 ∘ 𝑔):𝑥–1-1→𝑧)
8	7	ancoms 255	. . . . . . 7 ⊢ ((𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → (𝑓 ∘ 𝑔):𝑥–1-1→𝑧)
9		vex 2560	. . . . . . . . 9 ⊢ 𝑓 ∈ V
10		vex 2560	. . . . . . . . 9 ⊢ 𝑔 ∈ V
11	9, 10	coex 4863	. . . . . . . 8 ⊢ (𝑓 ∘ 𝑔) ∈ V
12		f1eq1 5087	. . . . . . . 8 ⊢ (ℎ = (𝑓 ∘ 𝑔) → (ℎ:𝑥–1-1→𝑧 ↔ (𝑓 ∘ 𝑔):𝑥–1-1→𝑧))
13	11, 12	spcev 2647	. . . . . . 7 ⊢ ((𝑓 ∘ 𝑔):𝑥–1-1→𝑧 → ∃ℎ ℎ:𝑥–1-1→𝑧)
14	8, 13	syl 14	. . . . . 6 ⊢ ((𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → ∃ℎ ℎ:𝑥–1-1→𝑧)
15	4	brdom 6231	. . . . . 6 ⊢ (𝑥 ≼ 𝑧 ↔ ∃ℎ ℎ:𝑥–1-1→𝑧)
16	14, 15	sylibr 137	. . . . 5 ⊢ ((𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
17	16	exlimivv 1776	. . . 4 ⊢ (∃𝑔∃𝑓(𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
18	6, 17	sylbir 125	. . 3 ⊢ ((∃𝑔 𝑔:𝑥–1-1→𝑦 ∧ ∃𝑓 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
19	3, 5, 18	syl2anb 275	. 2 ⊢ ((𝑥 ≼ 𝑦 ∧ 𝑦 ≼ 𝑧) → 𝑥 ≼ 𝑧)
20	1, 19	vtoclr 4388	1 ⊢ ((𝐴 ≼ 𝐵 ∧ 𝐵 ≼ 𝐶) → 𝐴 ≼ 𝐶)

Syntax hints:   → wi 4   ∧ wa 97  ∃wex 1381   class class class wbr 3764   ∘ ccom 4349  –1-1→wf1 4899   ≼ cdom 6220

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-13 1404  ax-14 1405  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022  ax-sep 3875  ax-pow 3927  ax-pr 3944  ax-un 4170

This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-eu 1903  df-mo 1904  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-rex 2312  df-v 2559  df-un 2922  df-in 2924  df-ss 2931  df-pw 3361  df-sn 3381  df-pr 3382  df-op 3384  df-uni 3581  df-br 3765  df-opab 3819  df-id 4030  df-xp 4351  df-rel 4352  df-cnv 4353  df-co 4354  df-dm 4355  df-rn 4356  df-fun 4904  df-fn 4905  df-f 4906  df-f1 4907  df-dom 6223

This theorem is referenced by:  endomtr  6270  domentr  6271  nndomo  6326