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Theorem reftr 23538
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 2735 . . . 4 𝐵 = 𝐵
2 eqid 2735 . . . 4 𝐶 = 𝐶
31, 2refbas 23534 . . 3 (𝐵Ref𝐶 𝐶 = 𝐵)
4 eqid 2735 . . . 4 𝐴 = 𝐴
54, 1refbas 23534 . . 3 (𝐴Ref𝐵 𝐵 = 𝐴)
63, 5sylan9eqr 2797 . 2 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐶 = 𝐴)
7 refssex 23535 . . . . . 6 ((𝐴Ref𝐵𝑥𝐴) → ∃𝑦𝐵 𝑥𝑦)
87ex 412 . . . . 5 (𝐴Ref𝐵 → (𝑥𝐴 → ∃𝑦𝐵 𝑥𝑦))
98adantr 480 . . . 4 ((𝐴Ref𝐵𝐵Ref𝐶) → (𝑥𝐴 → ∃𝑦𝐵 𝑥𝑦))
10 refssex 23535 . . . . . . 7 ((𝐵Ref𝐶𝑦𝐵) → ∃𝑧𝐶 𝑦𝑧)
1110ad2ant2lr 748 . . . . . 6 (((𝐴Ref𝐵𝐵Ref𝐶) ∧ (𝑦𝐵𝑥𝑦)) → ∃𝑧𝐶 𝑦𝑧)
12 sstr2 4002 . . . . . . . 8 (𝑥𝑦 → (𝑦𝑧𝑥𝑧))
1312reximdv 3168 . . . . . . 7 (𝑥𝑦 → (∃𝑧𝐶 𝑦𝑧 → ∃𝑧𝐶 𝑥𝑧))
1413ad2antll 729 . . . . . 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 23532 . . . . 5 Rel Ref
2019brrelex1i 5745 . . . 4 (𝐴Ref𝐵𝐴 ∈ V)
2120adantr 480 . . 3 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐴 ∈ V)
224, 2isref 23533 . . 3 (𝐴 ∈ V → (𝐴Ref𝐶 ↔ ( 𝐶 = 𝐴 ∧ ∀𝑥𝐴𝑧𝐶 𝑥𝑧)))
2321, 22syl 17 . 2 ((𝐴Ref𝐵𝐵Ref𝐶) → (𝐴Ref𝐶 ↔ ( 𝐶 = 𝐴 ∧ ∀𝑥𝐴𝑧𝐶 𝑥𝑧)))
246, 18, 23mpbir2and 713 1 ((𝐴Ref𝐵𝐵Ref𝐶) → 𝐴Ref𝐶)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 206  wa 395   = wceq 1537  wcel 2106  wral 3059  wrex 3068  Vcvv 3478  wss 3963   cuni 4912   class class class wbr 5148  Refcref 23526
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pow 5371  ax-pr 5438  ax-un 7754
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-sb 2063  df-clab 2713  df-cleq 2727  df-clel 2814  df-ral 3060  df-rex 3069  df-rab 3434  df-v 3480  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-pw 4607  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-br 5149  df-opab 5211  df-xp 5695  df-rel 5696  df-ref 23529
This theorem is referenced by:  refssfne  36341
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