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2025-02-25 WR

Rearrange the digits in ⟨125034⟩ to meet the rules below.

⟨5th 4th 3rd 2nd 1st 0th⟩

✅Match
Jump(2,5) = 2
⟦0,2⟧ ∋ 3,4

⛔Avoid
min ⊢3⊣ ≤ 2
5th → 0|1|3
⟨? ⋯ 1 ⋯ (?−2) ⋯⟩ (?≠3)

#125034_v2.8


       ┌───┬───┬───┬───┬───┬───┐
       │5th│4th│3rd│2nd│1st│0th│▒
       ╞═══╪═══╪═══╪═══╪═══╪═══╡▒
Step 1 │ 2 │   │   │   │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 2 │ 2 │   │   │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 3 │ 2 │   │ 3 │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 4 │ 2 │ 4 │ 3 │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 5 │ 2 │ 4 │ 3 │ 5 │   │ 1 │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 6 │ 2 │ 4 │ 3 │ 5 │ 0 │ 1 │▒
       └───┴───┴───┴───┴───┴───┘▒
        ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒

Proof of 2025-02-25 WR
══════════════════════

Notation: if nth -> a, then we write [nth] = a.

From ⛔「min ⊢3⊣ ≤ 2」, we see that 3 can only be adjacent to 4 or 5. As 3 is not in corners (5th or 0th) by ✅「⟦0,2⟧ ∋ 3,4」, we get the folloing required pattern:

(1) ⟨⋯ 435 ⋯⟩ or ⟨⋯ 534 ⋯⟩. 

Let us consider the value of [5th]. By ⛔「5th → 0|1|3」, it is 2|4|5. It has to be 2, for otherwise (1) implies

┌───┬───┬───┬───┬───┬───┐
│5th│4th│3rd│2nd│1st│0th│
╞═══╪═══╪═══╪═══╪═══╪═══╡
│ ▬ │ 3 │ ▬ │   │   │   │
└───┴───┴───┴───┴───┴───┘

where "▬" are occupied by 4 and 5. But then we cannot match ✅「⟦0,2⟧ ∋ 3,4」, which is a contradiction. 

As a result, we have

       ┌───┬───┬───┬───┬───┬───┐
       │ 5■│4th│3rd│2nd│1st│0th│▒
       ╞═══╪═══╪═══╪═══╪═══╪═══╡▒
Step 1 │ 2 │   │   │   │   │   │▒
       └───┴───┴───┴───┴───┴───┘▒
        ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒

--- Idle ---
┌───┬───┬───┬───┬───┬───┐
│ 1 │   │ 5 │ 0 │ 3 │ 4 │
└───┴───┴───┴───┴───┴───┘

Then, by ✅「Jump(2,5) = 2」, we get

       ┌───┬───┬───┬───┬───┬───┐
       │5th│4th│3rd│ 2■│1st│0th│▒
       ╞═══╪═══╪═══╪═══╪═══╪═══╡▒
       │ 2 │   │   │   │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 2 │ 2 │   │   │ 5 │   │   │▒
       └───┴───┴───┴───┴───┴───┘▒
        ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒

--- Idle ---
┌───┬───┬───┬───┬───┬───┐
│ 1 │   │   │ 0 │ 3 │ 4 │
└───┴───┴───┴───┴───┴───┘

Given [2nd] = 5, it follows from (1) that one of the following holds:

    ┌───┬───┬───┬───┬───┬───┐
    │5th│4th│3rd│2nd│1st│0th│
    ╞═══╪═══╪═══╪═══╪═══╪═══╡
(2) │ 2 │   │   │ 5 │ 3 │ 4 │
    ├───┼───┼───┼───┼───┼───┤
(3) │ 2 │ 4 │ 3 │ 5 │   │   │
    └───┴───┴───┴───┴───┴───┘

If (2) holds then we cannot match ✅「⟦0,2⟧ ∋ 3,4」. Therefore, (3) holds instead and we get

       ┌───┬───┬───┬───┬───┬───┐
       │5th│ 4■│ 3■│2nd│1st│0th│▒
       ╞═══╪═══╪═══╪═══╪═══╪═══╡▒
       │ 2 │   │   │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 3 │ 2 │   │ 3 │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 4 │ 2 │ 4 │ 3 │ 5 │   │   │▒
       └───┴───┴───┴───┴───┴───┘▒
        ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒

--- Idle ---
┌───┬───┬───┬───┬───┬───┐
│ 1 │   │   │ 0 │   │   │
└───┴───┴───┴───┴───┴───┘

Finally, to avoid ⛔「⟨? ⋯ 1 ⋯ (?−2) ⋯⟩ (?≠3)」, we finish by

       ┌───┬───┬───┬───┬───┬───┐
       │5th│4th│3rd│2nd│ 1■│ 0■│▒
       ╞═══╪═══╪═══╪═══╪═══╪═══╡▒
       │ 2 │ 4 │ 3 │ 5 │   │   │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 5 │ 2 │ 4 │ 3 │ 5 │   │ 1 │▒
       ├───┼───┼───┼───┼───┼───┤▒
Step 6 │ 2 │ 4 │ 3 │ 5 │ 0 │ 1 │▒
       └───┴───┴───┴───┴───┴───┘▒
        ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒

--- Idle ---
┌───┬───┬───┬───┬───┬───┐
│   │   │   │   │   │   │
└───┴───┴───┴───┴───┴───┘

Q.E.D.

#125034_v2.8