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2025-08-19 WR

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

⟨5th 4th 3rd 2nd 1st 0th⟩

✅Match
Jump(2,3) = 1
median {p5, p3, p0} = 3
4th → 0|2|4

⛔Avoid
Jump(0,2) = 0
median {p4, p3, p1} = 2
⟨⋯ 1 ⋯ 3 ⋯⟩
⟨⋯ 2 ⋯ ? 3 ⋯ (?+1)⟩ (?≠3,2)

#125034_v2.10


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

Proof of 2025-08-19 WR
══════════════════════

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

By ⛔「⟨⋯ 1 ⋯ 3 ⋯⟩」, 3 is not at 0th. Combining this with ✅「median {p5, p3, p0} = 3」, we have

(1) 3 = [5th] | [3rd].

(1.1) We show that 3 = [3rd] actually.

------------------------------

Suppose on the contrary 3 = [5th]:

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

Then, it follows from ✅「Jump(2,3) = 1」 that 2 = [3rd]:

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

To match ✅「4th → 0|2|4」, we need [4th] = 0 or 4. It is not 0 in view of ⛔「Jump(0,2) = 0」. Hence [4th] = 4:

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

Then, we consider where to place 0. By ⛔「Jump(0,2) = 0」, it is not at 2nd, and by ⛔「median {p4, p3, p1} = 2」, it is not at 1st either. Therefore, 0 = [0th]:

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

We have failed to match ✅「median {p5, p3, p0} = 3」, which is a contradiction.

------------------------------

We have verified (1.1). Accordingly, we get

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

--- Idle ---
┌───┬───┬───┬───┬───┬───┐
│ 1 │ 2 │ 5 │ 0 │   │ 4 │
└───┴───┴───┴───┴───┴───┘

Given that 3 = [3rd], to match ✅「Jump(2,3) = 1」 we need

(2) 2 = [5th] | [1st]:

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

(2.1) We show that 2 = [1st].

------------------------------

If on the contrary 2 = [5th]:

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

Then, to match ✅「4th → 0|2|4」 and avoid ⛔「Jump(0,2) = 0」 at the same time, we have [4th] = 4:

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

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

Note that there is only one way to match ✅「median {p5, p3, p0} = 3」:

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

But then we have matched ⛔「⟨⋯ 2 ⋯ ? 3 ⋯ (?+1)⟩ (?≠3,2)」, which is a contradiction.

------------------------------

We have verified (2.1). So we get

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

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

Next, we determine what [4th] is. To match ✅「4th → 0|2|4」 and avoid ⛔「median {p4, p3, p1} = 2」 at the same time, it has to be 4:

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

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

Then, plainly, there is only one way to avoid ⛔「Jump(0,2) = 0」:

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

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

Finally, to match ✅「median {p5, p3, p0} = 3」, we finish by

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

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

Q.E.D.

#125034_v2.10