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Theorem wlksnwwlknvbij 26803
Description: There is a bijection between the set of walks of a fixed length and the set of walks represented by words of the same length and starting at the same vertex. (Contributed by Alexander van der Vekens, 30-Sep-2018.) (Revised by AV, 20-Apr-2021.)
Assertion
Ref Expression
wlksnwwlknvbij ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → ∃𝑓 𝑓:{𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋})
Distinct variable groups:   𝑓,𝐺,𝑝,𝑤   𝑓,𝑁,𝑝,𝑤   𝑓,𝑋,𝑝,𝑤

Proof of Theorem wlksnwwlknvbij
Dummy variables 𝑞 𝑠 𝑡 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 fvex 6201 . . . . 5 (Walks‘𝐺) ∈ V
21mptrabex 6488 . . . 4 (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ∈ V
32resex 5443 . . 3 ((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}) ∈ V
4 eqid 2622 . . . 4 (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) = (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝))
5 usgruspgr 26073 . . . . . 6 (𝐺 ∈ USGraph → 𝐺 ∈ USPGraph )
6 fveq2 6191 . . . . . . . . . 10 (𝑞 = 𝑡 → (1st𝑞) = (1st𝑡))
76fveq2d 6195 . . . . . . . . 9 (𝑞 = 𝑡 → (#‘(1st𝑞)) = (#‘(1st𝑡)))
87eqeq1d 2624 . . . . . . . 8 (𝑞 = 𝑡 → ((#‘(1st𝑞)) = 𝑁 ↔ (#‘(1st𝑡)) = 𝑁))
98cbvrabv 3199 . . . . . . 7 {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} = {𝑡 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑡)) = 𝑁}
10 eqid 2622 . . . . . . 7 (𝑁 WWalksN 𝐺) = (𝑁 WWalksN 𝐺)
11 fveq2 6191 . . . . . . . 8 (𝑝 = 𝑠 → (2nd𝑝) = (2nd𝑠))
1211cbvmptv 4750 . . . . . . 7 (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) = (𝑠 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑠))
139, 10, 12wlknwwlksnbij 26777 . . . . . 6 ((𝐺 ∈ USPGraph ∧ 𝑁 ∈ ℕ0) → (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)):{𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁}–1-1-onto→(𝑁 WWalksN 𝐺))
145, 13sylan 488 . . . . 5 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0) → (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)):{𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁}–1-1-onto→(𝑁 WWalksN 𝐺))
15143adant3 1081 . . . 4 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)):{𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁}–1-1-onto→(𝑁 WWalksN 𝐺))
16 fveq1 6190 . . . . . 6 (𝑤 = (2nd𝑝) → (𝑤‘0) = ((2nd𝑝)‘0))
1716eqeq1d 2624 . . . . 5 (𝑤 = (2nd𝑝) → ((𝑤‘0) = 𝑋 ↔ ((2nd𝑝)‘0) = 𝑋))
18173ad2ant3 1084 . . . 4 (((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) ∧ 𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∧ 𝑤 = (2nd𝑝)) → ((𝑤‘0) = 𝑋 ↔ ((2nd𝑝)‘0) = 𝑋))
194, 15, 18f1oresrab 6395 . . 3 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → ((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}):{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋})
20 f1oeq1 6127 . . . 4 (𝑓 = ((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}) → (𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ↔ ((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}):{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋}))
2120spcegv 3294 . . 3 (((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}) ∈ V → (((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↦ (2nd𝑝)) ↾ {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}):{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} → ∃𝑓 𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋}))
223, 19, 21mpsyl 68 . 2 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → ∃𝑓 𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋})
23 df-rab 2921 . . . . 5 {𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)} = {𝑝 ∣ (𝑝 ∈ (Walks‘𝐺) ∧ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋))}
24 anass 681 . . . . . . 7 (((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋) ↔ (𝑝 ∈ (Walks‘𝐺) ∧ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)))
2524bicomi 214 . . . . . 6 ((𝑝 ∈ (Walks‘𝐺) ∧ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)) ↔ ((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋))
2625abbii 2739 . . . . 5 {𝑝 ∣ (𝑝 ∈ (Walks‘𝐺) ∧ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋))} = {𝑝 ∣ ((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋)}
27 fveq2 6191 . . . . . . . . . . . 12 (𝑞 = 𝑝 → (1st𝑞) = (1st𝑝))
2827fveq2d 6195 . . . . . . . . . . 11 (𝑞 = 𝑝 → (#‘(1st𝑞)) = (#‘(1st𝑝)))
2928eqeq1d 2624 . . . . . . . . . 10 (𝑞 = 𝑝 → ((#‘(1st𝑞)) = 𝑁 ↔ (#‘(1st𝑝)) = 𝑁))
3029elrab 3363 . . . . . . . . 9 (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ↔ (𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁))
3130anbi1i 731 . . . . . . . 8 ((𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∧ ((2nd𝑝)‘0) = 𝑋) ↔ ((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋))
3231bicomi 214 . . . . . . 7 (((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋) ↔ (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∧ ((2nd𝑝)‘0) = 𝑋))
3332abbii 2739 . . . . . 6 {𝑝 ∣ ((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋)} = {𝑝 ∣ (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∧ ((2nd𝑝)‘0) = 𝑋)}
34 df-rab 2921 . . . . . 6 {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋} = {𝑝 ∣ (𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∧ ((2nd𝑝)‘0) = 𝑋)}
3533, 34eqtr4i 2647 . . . . 5 {𝑝 ∣ ((𝑝 ∈ (Walks‘𝐺) ∧ (#‘(1st𝑝)) = 𝑁) ∧ ((2nd𝑝)‘0) = 𝑋)} = {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}
3623, 26, 353eqtri 2648 . . . 4 {𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)} = {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}
37 f1oeq2 6128 . . . 4 ({𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)} = {𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋} → (𝑓:{𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ↔ 𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋}))
3836, 37mp1i 13 . . 3 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → (𝑓:{𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ↔ 𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋}))
3938exbidv 1850 . 2 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → (∃𝑓 𝑓:{𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ↔ ∃𝑓 𝑓:{𝑝 ∈ {𝑞 ∈ (Walks‘𝐺) ∣ (#‘(1st𝑞)) = 𝑁} ∣ ((2nd𝑝)‘0) = 𝑋}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋}))
4022, 39mpbird 247 1 ((𝐺 ∈ USGraph ∧ 𝑁 ∈ ℕ0𝑋 ∈ (Vtx‘𝐺)) → ∃𝑓 𝑓:{𝑝 ∈ (Walks‘𝐺) ∣ ((#‘(1st𝑝)) = 𝑁 ∧ ((2nd𝑝)‘0) = 𝑋)}–1-1-onto→{𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋})
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 196  wa 384  w3a 1037   = wceq 1483  wex 1704  wcel 1990  {cab 2608  {crab 2916  Vcvv 3200  cmpt 4729  cres 5116  1-1-ontowf1o 5887  cfv 5888  (class class class)co 6650  1st c1st 7166  2nd c2nd 7167  0cc0 9936  0cn0 11292  #chash 13117  Vtxcvtx 25874   USPGraph cuspgr 26043   USGraph cusgr 26044  Walkscwlks 26492   WWalksN cwwlksn 26718
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949  ax-cnex 9992  ax-resscn 9993  ax-1cn 9994  ax-icn 9995  ax-addcl 9996  ax-addrcl 9997  ax-mulcl 9998  ax-mulrcl 9999  ax-mulcom 10000  ax-addass 10001  ax-mulass 10002  ax-distr 10003  ax-i2m1 10004  ax-1ne0 10005  ax-1rid 10006  ax-rnegex 10007  ax-rrecex 10008  ax-cnre 10009  ax-pre-lttri 10010  ax-pre-lttrn 10011  ax-pre-ltadd 10012  ax-pre-mulgt0 10013
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-ifp 1013  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-nel 2898  df-ral 2917  df-rex 2918  df-reu 2919  df-rmo 2920  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-int 4476  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-riota 6611  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-2o 7561  df-oadd 7564  df-er 7742  df-map 7859  df-pm 7860  df-en 7956  df-dom 7957  df-sdom 7958  df-fin 7959  df-card 8765  df-cda 8990  df-pnf 10076  df-mnf 10077  df-xr 10078  df-ltxr 10079  df-le 10080  df-sub 10268  df-neg 10269  df-nn 11021  df-2 11079  df-n0 11293  df-xnn0 11364  df-z 11378  df-uz 11688  df-fz 12327  df-fzo 12466  df-hash 13118  df-word 13299  df-edg 25940  df-uhgr 25953  df-upgr 25977  df-uspgr 26045  df-usgr 26046  df-wlks 26495  df-wwlks 26722  df-wwlksn 26723
This theorem is referenced by:  rusgrnumwlkg  26872
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