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Theorem reftr 22881
Description: Refinement is transitive. (Contributed by Jeff Hankins, 18-Jan-2010.) (Revised by Thierry Arnoux, 3-Feb-2020.)
Assertion
Ref Expression
reftr ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐴Ref𝐶)

Proof of Theorem reftr
Dummy variables 𝑥 𝑦 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 eqid 2737 . . . 4 𝐵 = 𝐵
2 eqid 2737 . . . 4 𝐶 = 𝐶
31, 2refbas 22877 . . 3 (𝐵Ref𝐶 𝐶 = 𝐵)
4 eqid 2737 . . . 4 𝐴 = 𝐴
54, 1refbas 22877 . . 3 (𝐴Ref𝐵 𝐵 = 𝐴)
63, 5sylan9eqr 2799 . 2 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐶 = 𝐴)
7 refssex 22878 . . . . . 6 ((𝐴Ref𝐵𝑥𝐴) → ∃𝑦𝐵 𝑥𝑦)
87ex 414 . . . . 5 (𝐴Ref𝐵 → (𝑥𝐴 → ∃𝑦𝐵 𝑥𝑦))
98adantr 482 . . . 4 ((𝐴Ref𝐵𝐵Ref𝐶) → (𝑥𝐴 → ∃𝑦𝐵 𝑥𝑦))
10 refssex 22878 . . . . . . 7 ((𝐵Ref𝐶𝑦𝐵) → ∃𝑧𝐶 𝑦𝑧)
1110ad2ant2lr 747 . . . . . 6 (((𝐴Ref𝐵𝐵Ref𝐶) ∧ (𝑦𝐵𝑥𝑦)) → ∃𝑧𝐶 𝑦𝑧)
12 sstr2 3956 . . . . . . . 8 (𝑥𝑦 → (𝑦𝑧𝑥𝑧))
1312reximdv 3168 . . . . . . 7 (𝑥𝑦 → (∃𝑧𝐶 𝑦𝑧 → ∃𝑧𝐶 𝑥𝑧))
1413ad2antll 728 . . . . . 6 (((𝐴Ref𝐵𝐵Ref𝐶) ∧ (𝑦𝐵𝑥𝑦)) → (∃𝑧𝐶 𝑦𝑧 → ∃𝑧𝐶 𝑥𝑧))
1511, 14mpd 15 . . . . 5 (((𝐴Ref𝐵𝐵Ref𝐶) ∧ (𝑦𝐵𝑥𝑦)) → ∃𝑧𝐶 𝑥𝑧)
1615rexlimdvaa 3154 . . . 4 ((𝐴Ref𝐵𝐵Ref𝐶) → (∃𝑦𝐵 𝑥𝑦 → ∃𝑧𝐶 𝑥𝑧))
179, 16syld 47 . . 3 ((𝐴Ref𝐵𝐵Ref𝐶) → (𝑥𝐴 → ∃𝑧𝐶 𝑥𝑧))
1817ralrimiv 3143 . 2 ((𝐴Ref𝐵𝐵Ref𝐶) → ∀𝑥𝐴𝑧𝐶 𝑥𝑧)
19 refrel 22875 . . . . 5 Rel Ref
2019brrelex1i 5693 . . . 4 (𝐴Ref𝐵𝐴 ∈ V)
2120adantr 482 . . 3 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐴 ∈ V)
224, 2isref 22876 . . 3 (𝐴 ∈ V → (𝐴Ref𝐶 ↔ ( 𝐶 = 𝐴 ∧ ∀𝑥𝐴𝑧𝐶 𝑥𝑧)))
2321, 22syl 17 . 2 ((𝐴Ref𝐵𝐵Ref𝐶) → (𝐴Ref𝐶 ↔ ( 𝐶 = 𝐴 ∧ ∀𝑥𝐴𝑧𝐶 𝑥𝑧)))
246, 18, 23mpbir2and 712 1 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐴Ref𝐶)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 397   = wceq 1542  wcel 2107  wral 3065  wrex 3074  Vcvv 3448  wss 3915   cuni 4870   class class class wbr 5110  Refcref 22869
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-ext 2708  ax-sep 5261  ax-nul 5268  ax-pow 5325  ax-pr 5389  ax-un 7677
This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-sb 2069  df-clab 2715  df-cleq 2729  df-clel 2815  df-ral 3066  df-rex 3075  df-rab 3411  df-v 3450  df-dif 3918  df-un 3920  df-in 3922  df-ss 3932  df-nul 4288  df-if 4492  df-pw 4567  df-sn 4592  df-pr 4594  df-op 4598  df-uni 4871  df-br 5111  df-opab 5173  df-xp 5644  df-rel 5645  df-ref 22872
This theorem is referenced by:  refssfne  34859
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