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Theorem efgrelexlema 18208
Description: If two words 𝐴, 𝐵 are related under the free group equivalence, then there exist two extension sequences 𝑎, 𝑏 such that 𝑎 ends at 𝐴, 𝑏 ends at 𝐵, and 𝑎 and 𝐵 have the same starting point. (Contributed by Mario Carneiro, 1-Oct-2015.)
Hypotheses
Ref Expression
efgval.w 𝑊 = ( I ‘Word (𝐼 × 2𝑜))
efgval.r = ( ~FG𝐼)
efgval2.m 𝑀 = (𝑦𝐼, 𝑧 ∈ 2𝑜 ↦ ⟨𝑦, (1𝑜𝑧)⟩)
efgval2.t 𝑇 = (𝑣𝑊 ↦ (𝑛 ∈ (0...(#‘𝑣)), 𝑤 ∈ (𝐼 × 2𝑜) ↦ (𝑣 splice ⟨𝑛, 𝑛, ⟨“𝑤(𝑀𝑤)”⟩⟩)))
efgred.d 𝐷 = (𝑊 𝑥𝑊 ran (𝑇𝑥))
efgred.s 𝑆 = (𝑚 ∈ {𝑡 ∈ (Word 𝑊 ∖ {∅}) ∣ ((𝑡‘0) ∈ 𝐷 ∧ ∀𝑘 ∈ (1..^(#‘𝑡))(𝑡𝑘) ∈ ran (𝑇‘(𝑡‘(𝑘 − 1))))} ↦ (𝑚‘((#‘𝑚) − 1)))
efgrelexlem.1 𝐿 = {⟨𝑖, 𝑗⟩ ∣ ∃𝑐 ∈ (𝑆 “ {𝑖})∃𝑑 ∈ (𝑆 “ {𝑗})(𝑐‘0) = (𝑑‘0)}
Assertion
Ref Expression
efgrelexlema (𝐴𝐿𝐵 ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0))
Distinct variable groups:   𝑎,𝑏,𝑐,𝑑,𝑖,𝑗,𝐴   𝑦,𝑎,𝑧,𝑏   𝐿,𝑎,𝑏   𝑛,𝑐,𝑡,𝑣,𝑤,𝑦,𝑧   𝑚,𝑎,𝑛,𝑡,𝑣,𝑤,𝑥,𝑀,𝑏,𝑐,𝑖,𝑗   𝑘,𝑎,𝑇,𝑏,𝑐,𝑖,𝑗,𝑚,𝑡,𝑥   𝑊,𝑎,𝑏,𝑐   𝑘,𝑑,𝑚,𝑛,𝑡,𝑣,𝑤,𝑥,𝑦,𝑧,𝑊,𝑖,𝑗   ,𝑎,𝑏,𝑐,𝑑,𝑖,𝑗,𝑚,𝑡,𝑥,𝑦,𝑧   𝐵,𝑎,𝑏,𝑐,𝑑,𝑖,𝑗   𝑆,𝑎,𝑏,𝑐,𝑑,𝑖,𝑗   𝐼,𝑎,𝑏,𝑐,𝑖,𝑗,𝑚,𝑛,𝑡,𝑣,𝑤,𝑥,𝑦,𝑧   𝐷,𝑎,𝑏,𝑐,𝑑,𝑖,𝑗,𝑚,𝑡
Allowed substitution hints:   𝐴(𝑥,𝑦,𝑧,𝑤,𝑣,𝑡,𝑘,𝑚,𝑛)   𝐵(𝑥,𝑦,𝑧,𝑤,𝑣,𝑡,𝑘,𝑚,𝑛)   𝐷(𝑥,𝑦,𝑧,𝑤,𝑣,𝑘,𝑛)   (𝑤,𝑣,𝑘,𝑛)   𝑆(𝑥,𝑦,𝑧,𝑤,𝑣,𝑡,𝑘,𝑚,𝑛)   𝑇(𝑦,𝑧,𝑤,𝑣,𝑛,𝑑)   𝐼(𝑘,𝑑)   𝐿(𝑥,𝑦,𝑧,𝑤,𝑣,𝑡,𝑖,𝑗,𝑘,𝑚,𝑛,𝑐,𝑑)   𝑀(𝑦,𝑧,𝑘,𝑑)

Proof of Theorem efgrelexlema
StepHypRef Expression
1 efgrelexlem.1 . . 3 𝐿 = {⟨𝑖, 𝑗⟩ ∣ ∃𝑐 ∈ (𝑆 “ {𝑖})∃𝑑 ∈ (𝑆 “ {𝑗})(𝑐‘0) = (𝑑‘0)}
21bropaex12 5226 . 2 (𝐴𝐿𝐵 → (𝐴 ∈ V ∧ 𝐵 ∈ V))
3 n0i 3953 . . . . . 6 (𝑎 ∈ (𝑆 “ {𝐴}) → ¬ (𝑆 “ {𝐴}) = ∅)
4 snprc 4285 . . . . . . . 8 𝐴 ∈ V ↔ {𝐴} = ∅)
5 imaeq2 5497 . . . . . . . 8 ({𝐴} = ∅ → (𝑆 “ {𝐴}) = (𝑆 “ ∅))
64, 5sylbi 207 . . . . . . 7 𝐴 ∈ V → (𝑆 “ {𝐴}) = (𝑆 “ ∅))
7 ima0 5516 . . . . . . 7 (𝑆 “ ∅) = ∅
86, 7syl6eq 2701 . . . . . 6 𝐴 ∈ V → (𝑆 “ {𝐴}) = ∅)
93, 8nsyl2 142 . . . . 5 (𝑎 ∈ (𝑆 “ {𝐴}) → 𝐴 ∈ V)
10 n0i 3953 . . . . . 6 (𝑏 ∈ (𝑆 “ {𝐵}) → ¬ (𝑆 “ {𝐵}) = ∅)
11 snprc 4285 . . . . . . . 8 𝐵 ∈ V ↔ {𝐵} = ∅)
12 imaeq2 5497 . . . . . . . 8 ({𝐵} = ∅ → (𝑆 “ {𝐵}) = (𝑆 “ ∅))
1311, 12sylbi 207 . . . . . . 7 𝐵 ∈ V → (𝑆 “ {𝐵}) = (𝑆 “ ∅))
1413, 7syl6eq 2701 . . . . . 6 𝐵 ∈ V → (𝑆 “ {𝐵}) = ∅)
1510, 14nsyl2 142 . . . . 5 (𝑏 ∈ (𝑆 “ {𝐵}) → 𝐵 ∈ V)
169, 15anim12i 589 . . . 4 ((𝑎 ∈ (𝑆 “ {𝐴}) ∧ 𝑏 ∈ (𝑆 “ {𝐵})) → (𝐴 ∈ V ∧ 𝐵 ∈ V))
1716a1d 25 . . 3 ((𝑎 ∈ (𝑆 “ {𝐴}) ∧ 𝑏 ∈ (𝑆 “ {𝐵})) → ((𝑎‘0) = (𝑏‘0) → (𝐴 ∈ V ∧ 𝐵 ∈ V)))
1817rexlimivv 3065 . 2 (∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0) → (𝐴 ∈ V ∧ 𝐵 ∈ V))
19 fveq1 6228 . . . . . 6 (𝑐 = 𝑎 → (𝑐‘0) = (𝑎‘0))
2019eqeq1d 2653 . . . . 5 (𝑐 = 𝑎 → ((𝑐‘0) = (𝑑‘0) ↔ (𝑎‘0) = (𝑑‘0)))
21 fveq1 6228 . . . . . 6 (𝑑 = 𝑏 → (𝑑‘0) = (𝑏‘0))
2221eqeq2d 2661 . . . . 5 (𝑑 = 𝑏 → ((𝑎‘0) = (𝑑‘0) ↔ (𝑎‘0) = (𝑏‘0)))
2320, 22cbvrex2v 3210 . . . 4 (∃𝑐 ∈ (𝑆 “ {𝑖})∃𝑑 ∈ (𝑆 “ {𝑗})(𝑐‘0) = (𝑑‘0) ↔ ∃𝑎 ∈ (𝑆 “ {𝑖})∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0))
24 sneq 4220 . . . . . 6 (𝑖 = 𝐴 → {𝑖} = {𝐴})
2524imaeq2d 5501 . . . . 5 (𝑖 = 𝐴 → (𝑆 “ {𝑖}) = (𝑆 “ {𝐴}))
2625rexeqdv 3175 . . . 4 (𝑖 = 𝐴 → (∃𝑎 ∈ (𝑆 “ {𝑖})∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0) ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0)))
2723, 26syl5bb 272 . . 3 (𝑖 = 𝐴 → (∃𝑐 ∈ (𝑆 “ {𝑖})∃𝑑 ∈ (𝑆 “ {𝑗})(𝑐‘0) = (𝑑‘0) ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0)))
28 sneq 4220 . . . . . 6 (𝑗 = 𝐵 → {𝑗} = {𝐵})
2928imaeq2d 5501 . . . . 5 (𝑗 = 𝐵 → (𝑆 “ {𝑗}) = (𝑆 “ {𝐵}))
3029rexeqdv 3175 . . . 4 (𝑗 = 𝐵 → (∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0) ↔ ∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0)))
3130rexbidv 3081 . . 3 (𝑗 = 𝐵 → (∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝑗})(𝑎‘0) = (𝑏‘0) ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0)))
3227, 31, 1brabg 5023 . 2 ((𝐴 ∈ V ∧ 𝐵 ∈ V) → (𝐴𝐿𝐵 ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0)))
332, 18, 32pm5.21nii 367 1 (𝐴𝐿𝐵 ↔ ∃𝑎 ∈ (𝑆 “ {𝐴})∃𝑏 ∈ (𝑆 “ {𝐵})(𝑎‘0) = (𝑏‘0))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wb 196  wa 383   = wceq 1523  wcel 2030  wral 2941  wrex 2942  {crab 2945  Vcvv 3231  cdif 3604  c0 3948  {csn 4210  cop 4216  cotp 4218   ciun 4552   class class class wbr 4685  {copab 4745  cmpt 4762   I cid 5052   × cxp 5141  ccnv 5142  ran crn 5144  cima 5146  cfv 5926  (class class class)co 6690  cmpt2 6692  1𝑜c1o 7598  2𝑜c2o 7599  0cc0 9974  1c1 9975  cmin 10304  ...cfz 12364  ..^cfzo 12504  #chash 13157  Word cword 13323   splice csplice 13328  ⟨“cs2 13632   ~FG cefg 18165
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631  ax-sep 4814  ax-nul 4822  ax-pr 4936
This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3an 1056  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-eu 2502  df-mo 2503  df-clab 2638  df-cleq 2644  df-clel 2647  df-nfc 2782  df-ral 2946  df-rex 2947  df-rab 2950  df-v 3233  df-dif 3610  df-un 3612  df-in 3614  df-ss 3621  df-nul 3949  df-if 4120  df-sn 4211  df-pr 4213  df-op 4217  df-uni 4469  df-br 4686  df-opab 4746  df-xp 5149  df-cnv 5151  df-dm 5153  df-rn 5154  df-res 5155  df-ima 5156  df-iota 5889  df-fv 5934
This theorem is referenced by:  efgrelexlemb  18209  efgrelex  18210
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