Theorem domtr 6633

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 6593	. 2 ⊢ Rel ≼
2		vex 2660	. . . 4 ⊢ 𝑦 ∈ V
3	2	brdom 6598	. . 3 ⊢ (𝑥 ≼ 𝑦 ↔ ∃𝑔 𝑔:𝑥–1-1→𝑦)
4		vex 2660	. . . 4 ⊢ 𝑧 ∈ V
5	4	brdom 6598	. . 3 ⊢ (𝑦 ≼ 𝑧 ↔ ∃𝑓 𝑓:𝑦–1-1→𝑧)
6		eeanv 1882	. . . 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 5298	. . . . . . . 8 ⊢ ((𝑓:𝑦–1-1→𝑧 ∧ 𝑔:𝑥–1-1→𝑦) → (𝑓 ∘ 𝑔):𝑥–1-1→𝑧)
8	7	ancoms 266	. . . . . . 7 ⊢ ((𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → (𝑓 ∘ 𝑔):𝑥–1-1→𝑧)
9		vex 2660	. . . . . . . . 9 ⊢ 𝑓 ∈ V
10		vex 2660	. . . . . . . . 9 ⊢ 𝑔 ∈ V
11	9, 10	coex 5042	. . . . . . . 8 ⊢ (𝑓 ∘ 𝑔) ∈ V
12		f1eq1 5281	. . . . . . . 8 ⊢ (ℎ = (𝑓 ∘ 𝑔) → (ℎ:𝑥–1-1→𝑧 ↔ (𝑓 ∘ 𝑔):𝑥–1-1→𝑧))
13	11, 12	spcev 2751	. . . . . . 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 6598	. . . . . 6 ⊢ (𝑥 ≼ 𝑧 ↔ ∃ℎ ℎ:𝑥–1-1→𝑧)
16	14, 15	sylibr 133	. . . . 5 ⊢ ((𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
17	16	exlimivv 1850	. . . 4 ⊢ (∃𝑔∃𝑓(𝑔:𝑥–1-1→𝑦 ∧ 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
18	6, 17	sylbir 134	. . 3 ⊢ ((∃𝑔 𝑔:𝑥–1-1→𝑦 ∧ ∃𝑓 𝑓:𝑦–1-1→𝑧) → 𝑥 ≼ 𝑧)
19	3, 5, 18	syl2anb 287	. 2 ⊢ ((𝑥 ≼ 𝑦 ∧ 𝑦 ≼ 𝑧) → 𝑥 ≼ 𝑧)
20	1, 19	vtoclr 4547	1 ⊢ ((𝐴 ≼ 𝐵 ∧ 𝐵 ≼ 𝐶) → 𝐴 ≼ 𝐶)

Syntax hints:   → wi 4   ∧ wa 103  ∃wex 1451   class class class wbr 3895   ∘ ccom 4503  –1-1→wf1 5078   ≼ cdom 6587

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 681  ax-5 1406  ax-7 1407  ax-gen 1408  ax-ie1 1452  ax-ie2 1453  ax-8 1465  ax-10 1466  ax-11 1467  ax-i12 1468  ax-bndl 1469  ax-4 1470  ax-13 1474  ax-14 1475  ax-17 1489  ax-i9 1493  ax-ial 1497  ax-i5r 1498  ax-ext 2097  ax-sep 4006  ax-pow 4058  ax-pr 4091  ax-un 4315

This theorem depends on definitions:  df-bi 116  df-3an 947  df-tru 1317  df-nf 1420  df-sb 1719  df-eu 1978  df-mo 1979  df-clab 2102  df-cleq 2108  df-clel 2111  df-nfc 2244  df-ral 2395  df-rex 2396  df-v 2659  df-un 3041  df-in 3043  df-ss 3050  df-pw 3478  df-sn 3499  df-pr 3500  df-op 3502  df-uni 3703  df-br 3896  df-opab 3950  df-id 4175  df-xp 4505  df-rel 4506  df-cnv 4507  df-co 4508  df-dm 4509  df-rn 4510  df-fun 5083  df-fn 5084  df-f 5085  df-f1 5086  df-dom 6590

This theorem is referenced by:  endomtr  6638  domentr  6639  cnvct  6657  ssct  6665  nndomo  6711  infnfi  6742  xpct  11754