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Theorem clwwlknclwwlkdifs 26774
Description: The set of walks of length n starting with a fixed vertex and ending not at this vertex is the difference between the set of walks of length n starting with this vertex and the set of walks of length n starting with this vertex and ending at this vertex. (Contributed by Alexander van der Vekens, 30-Sep-2018.) (Revised by AV, 7-May-2021.)
Hypotheses
Ref Expression
clwwlknclwwlkdif.a 𝐴 = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)}
clwwlknclwwlkdif.b 𝐵 = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)}
Assertion
Ref Expression
clwwlknclwwlkdifs 𝐴 = ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ 𝐵)

Proof of Theorem clwwlknclwwlkdifs
StepHypRef Expression
1 clwwlknclwwlkdif.a . 2 𝐴 = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)}
2 clwwlknclwwlkdif.b . . . 4 𝐵 = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)}
32difeq2i 3709 . . 3 ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ 𝐵) = ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)})
4 difrab 3883 . . 3 ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)}) = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋))}
5 ianor 509 . . . . . . . 8 (¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋) ↔ (¬ ( lastS ‘𝑤) = (𝑤‘0) ∨ ¬ (𝑤‘0) = 𝑋))
6 eqeq2 2632 . . . . . . . . . . . 12 ((𝑤‘0) = 𝑋 → (( lastS ‘𝑤) = (𝑤‘0) ↔ ( lastS ‘𝑤) = 𝑋))
76notbid 308 . . . . . . . . . . 11 ((𝑤‘0) = 𝑋 → (¬ ( lastS ‘𝑤) = (𝑤‘0) ↔ ¬ ( lastS ‘𝑤) = 𝑋))
8 neqne 2798 . . . . . . . . . . . . 13 (¬ ( lastS ‘𝑤) = 𝑋 → ( lastS ‘𝑤) ≠ 𝑋)
98anim2i 592 . . . . . . . . . . . 12 (((𝑤‘0) = 𝑋 ∧ ¬ ( lastS ‘𝑤) = 𝑋) → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋))
109ex 450 . . . . . . . . . . 11 ((𝑤‘0) = 𝑋 → (¬ ( lastS ‘𝑤) = 𝑋 → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
117, 10sylbid 230 . . . . . . . . . 10 ((𝑤‘0) = 𝑋 → (¬ ( lastS ‘𝑤) = (𝑤‘0) → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
1211com12 32 . . . . . . . . 9 (¬ ( lastS ‘𝑤) = (𝑤‘0) → ((𝑤‘0) = 𝑋 → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
13 pm2.21 120 . . . . . . . . 9 (¬ (𝑤‘0) = 𝑋 → ((𝑤‘0) = 𝑋 → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
1412, 13jaoi 394 . . . . . . . 8 ((¬ ( lastS ‘𝑤) = (𝑤‘0) ∨ ¬ (𝑤‘0) = 𝑋) → ((𝑤‘0) = 𝑋 → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
155, 14sylbi 207 . . . . . . 7 (¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋) → ((𝑤‘0) = 𝑋 → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
1615impcom 446 . . . . . 6 (((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)) → ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋))
17 simpl 473 . . . . . . 7 (((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋) → (𝑤‘0) = 𝑋)
18 neeq2 2853 . . . . . . . . . . 11 (𝑋 = (𝑤‘0) → (( lastS ‘𝑤) ≠ 𝑋 ↔ ( lastS ‘𝑤) ≠ (𝑤‘0)))
1918eqcoms 2629 . . . . . . . . . 10 ((𝑤‘0) = 𝑋 → (( lastS ‘𝑤) ≠ 𝑋 ↔ ( lastS ‘𝑤) ≠ (𝑤‘0)))
20 neneq 2796 . . . . . . . . . 10 (( lastS ‘𝑤) ≠ (𝑤‘0) → ¬ ( lastS ‘𝑤) = (𝑤‘0))
2119, 20syl6bi 243 . . . . . . . . 9 ((𝑤‘0) = 𝑋 → (( lastS ‘𝑤) ≠ 𝑋 → ¬ ( lastS ‘𝑤) = (𝑤‘0)))
2221imp 445 . . . . . . . 8 (((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋) → ¬ ( lastS ‘𝑤) = (𝑤‘0))
2322intnanrd 962 . . . . . . 7 (((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋) → ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋))
2417, 23jca 554 . . . . . 6 (((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋) → ((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)))
2516, 24impbii 199 . . . . 5 (((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)) ↔ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋))
2625a1i 11 . . . 4 (𝑤 ∈ (𝑁 WWalksN 𝐺) → (((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋)) ↔ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)))
2726rabbiia 3177 . . 3 {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ¬ (( lastS ‘𝑤) = (𝑤‘0) ∧ (𝑤‘0) = 𝑋))} = {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)}
283, 4, 273eqtrri 2648 . 2 {𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ ((𝑤‘0) = 𝑋 ∧ ( lastS ‘𝑤) ≠ 𝑋)} = ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ 𝐵)
291, 28eqtri 2643 1 𝐴 = ({𝑤 ∈ (𝑁 WWalksN 𝐺) ∣ (𝑤‘0) = 𝑋} ∖ 𝐵)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 196  wo 383  wa 384   = wceq 1480  wcel 1987  wne 2790  {crab 2912  cdif 3557  cfv 5857  (class class class)co 6615  0cc0 9896   lastS clsw 13247   WWalksN cwwlksn 26621
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-9 1996  ax-10 2016  ax-11 2031  ax-12 2044  ax-13 2245  ax-ext 2601
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1878  df-clab 2608  df-cleq 2614  df-clel 2617  df-nfc 2750  df-ne 2791  df-ral 2913  df-rab 2917  df-v 3192  df-dif 3563
This theorem is referenced by:  clwwlknclwwlkdifnum  26775
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