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2025-03-25 WR

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

⟨5th 4th 3rd 2nd 1st 0th⟩

✅Match
⟨⋯ Perm(0,2,4) ⋯⟩
5th → a, 2nd → b, |a-b|=1
⟨ ⁵ᵗʰa     ²ⁿᵈb     ⟩, min⟦a,b⟧ = 0

⛔Avoid
⟨⋯ Perm(0,3) ⋯⟩
{p4, p2, p1} = ? + {0,2,3}
Jump(1,2) ≥ 2
5th|2nd|0th → 0
max ⊢3⊣ = 3

#125034_v2.8


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

Proof of 2025-03-25 WR
══════════════════════

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

By ✅「⟨ ⁵ᵗʰa     ²ⁿᵈb     ⟩, min⟦a,b⟧ = 0」 and ⛔「5th|2nd|0th → 0」, we have

(1) 0 = [4th] | [3rd].

(2) We show that 2 = [2nd]. It is proved by contradiction.

Suppose on the contrary that 2 != [2nd]. Then

2 = [5th] | [4th] | [3rd] | [1st] | [0th].

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

(2.1) If 2 = [5th]:

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

then ✅「⟨⋯ Perm(0,2,4) ⋯⟩」 implies

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

where ▬ are occupied by 0,4. But then we cannot avoid ⛔「Jump(1,2) ≥ 2」, which is a contradiction.

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

(2.2) Else if 2 = [4th]:

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

then by (1), we have

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

In view of ✅「⟨⋯ Perm(0,2,4) ⋯⟩」, one of the following holds:

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

No matter which happens, we use ⛔「Jump(1,2) ≥ 2」 and get

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

Note that we fail to match ✅「5th → a, 2nd → b, |a-b|=1」, which is a contradiction.

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

(2.3) Else if 2 = [3rd]:

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

then (1) implies

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

In view of ✅「⟨⋯ Perm(0,2,4) ⋯⟩」, one of the following holds:

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

Consider case (A) first:

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

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

To avoid ⛔「max ⊢3⊣ = 3」, we need 3,5 to be adjacent. The possible cases are:

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

However, the first disagrees with ⛔「Jump(1,2) ≥ 2」, while the second disagrees with ✅「5th → a, 2nd → b, |a-b|=1」.

So, case (A) does not hold, and case (B) holds instead:

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

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

To match ✅「5th → a, 2nd → b, |a-b|=1」 and avoid ⛔「⟨⋯ Perm(0,3) ⋯⟩」 at the same time, we have

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

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

But then we cannot avoid ⛔「Jump(1,2) ≥ 2」 and ⛔「max ⊢3⊣ = 3」 at the same time. It shows a contradiction. 

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

(2.4) Else if 2 = [1st]:

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

Then, to match ✅「⟨⋯ Perm(0,2,4) ⋯⟩」 and (1) at the same time, we need

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

By ⛔「Jump(1,2) ≥ 2」 and ⛔「⟨⋯ Perm(0,3) ⋯⟩」, we get

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

It matches ⛔「{p4, p2, p1} = ? + {0,2,3}」 however, which is a contradiction.

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

(2.5) Lastly, suppose 2 = [0th]:

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

Note that we cannot match ✅「⟨⋯ Perm(0,2,4) ⋯⟩」 and (1) at the same time. It shows a contradiction.

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

By (2.1)-(2.5), we have verified (2). Accordingly, we get

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

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

Then, by ✅「5th → a, 2nd → b, |a-b|=1」, we have [5th] = 1|3. In view of ⛔「Jump(1,2) ≥ 2」, it is 3 indeed:

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

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

By (1), we have 0 = [4th] | [3rd]. To avoid ⛔「⟨⋯ Perm(0,3) ⋯⟩」, we get 0 = [3rd]:

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

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

Next, we consider the value of [0th]. To match ✅「⟨⋯ Perm(0,2,4) ⋯⟩」, it is not 4; on the other hand, if it is 1, then

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

where ▬ are occupied by 4,5. This however matches ⛔「{p4, p2, p1} = ? + {0,2,3}」, which is a contradiction. Therefore, we need [0th] != 1 as well.

Consequently, [0th] = 5:

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

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

Finally, to avoid ⛔「max ⊢3⊣ = 3」, we finish by

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

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

Q.E.D.

#125034_v2.8