User:Polygon/Page for testing

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1RB1RD1LC_2LB1RB1LC_1RZ1LA1LD_2RB2RA2RD (bbch) is a pentational halting BB(4,3) TM. It was discovered in May 2024 by Pavel Kropitz as one of seven long running TMs and achieves a score of over 245<math>,makingittheBB(4,3)champion.==Analysis==<pre>Sisanytapeconfiguration1.SD>2aS>S2aD>S[+asteps]2.SB>1aS>S1aB>S[+asteps]3.SA>02S>S<A12S[+5steps]4.SD>(11)aS>S(21)aD>S[+2asteps]SA>(11)aS>S(12)aA>S[+2asteps]5.S(21)a<CS>S<C(11)aS[+2asteps]S(12)a<AS>S<A(11)aS[+2asteps]6.S(12)aA>02S>S<A(11)a+1S[+2a+5steps]7.SA>(11)12bS>S2A>(11)12b1S[+5steps]8.SA>(11)12bS>S2bA>(11)1S[+5bsteps]9.SD>02S>S<B22S[+3steps]10.S2<D(11)a02S>S<D(11)a+12S[+4a+7steps]11.S2<D(11)a202S>S<D(11)a+122S[+4a+7steps]12.S1a<A(11)b02S>S1a1<A(11)b+12S[+4b+7steps]13.S1a<A(11)b202S>S1a1<A(11)b+122S[+4b+7steps]14.S(12)a1<D(11)b02S>S(12)a11<D(11)b+2[+4b+8steps]15.S(12)a1<D(11)b0inf>S1<D(11)b+2a0inf[+4a2+4ba+4asteps]16.S(12)a21<D(11)b0inf>S(12)a12(12)b+21<D(11)10inf[+10b+28steps]17.S(12)a21<D(11)b0inf>S(12)a121<D(11)2b+50inf18.S(12)a21<D(11)b0inf>S21<D(11)(2a)*b+(2a)*550inf19.S(12)a21<D(11)b20inf>S(12)a221<D(11)2b10inf20.S(12)a1<D(11)b20inf>S(12)a21<D(11)2b10inf21.S(12)a221<D(11)b0inf>S(12)a1221<D(11)2(b+4)*350inf22.S1<D(11)b220inf>S2(12)b121<D(11)10inf23.S(11)a221<D(11)b0inf>S(11)a3(12)2b+11221<D(11)10inf24.0inf221<D(11)c0inf>0inf(11)c+1(12)3221<D(11)10inf25.0inf(11)2221<D(11)c0inf>0inf1(11)2c+8(12)3221<D(11)10inf26.0inf1(11)1221<D(11)c0inf>0inf1(11)2c+7(12)3221<D(11)10inf27.0inf1221<D(11)c0inf>0inf(11)2c+5(12)3221<D(11)10inf28.0inf(11)1221<D(11)c0inf>0inf1Z>1(11)2c+80inf</pre>LetD(a,b,c)=0inf(11)a(12)b221<D(11)c0infLetD1(a,b,c)=0inf1(11)a(12)b221<D(11)c0infLet<math>f1(n)=2n+4×35

Let f2(a,b)=f12×f2(a1,b)+11(1), wheref2(0,b)=b

Rule 21 becomes:

  • D(a,b,c)>D(a,b1,2b+4×35)
  • D1(a,b,c)>D1(a,b1,2b+4×35)

Rule 23 becomes:

  • D(a,0,c)>D(a3,2c+11,1)
  • D1(a,0,c)>D1(a3,2c+11,1)

Rule 24 becomes:

  • D(0,0,c)>D(c+1,3,1)

Rule 25 becomes:

  • D(2,0,c)>D(2c+8,3,1)

Rule 26 becomes:

  • D1(1,0,c)>D1(2c+7,3,1)

Rule 27 becomes:

  • D1(0,0,c)>D(2c+5,3,1)

Rule 28 becomes:

  • D(1, 0, c) --> halt with score 4c + 18

Rule 29 becomes:

  • D1(2,0,c)>D(2c+10,2,1)

By repeating rule 21, a stronger rule can be constructed:

  • D(a,b,c)>D(a,0,f1b(c))
  • D1(a,b,c)>D1(a,0,f1b(c))

If a is greater than or equal to 3: D(a,0,c)>D(a3,2c+11,1)>D(a3,0,f12c+11(1)) =D(a3,0,f2(1,c))

  • D(a,0,c)>D(a3,0,f12c+11(1))

This rule can also be repeated, also note that f12c+11(1)=f2(1,c) and f12×f2(a,b)+11(1)=f2(a+1,b):

  • D(3k+d,0,c)>D(d,0,f2(k,c))
  • D1(3k+d,0,c)>D1(d,0,f2(k,c))

The TM starts in configuration D(2, 2, 1).

D(2, 2, 1) -->

D(2,0,f12(1))=D(2,0,f1(91))

e1=f1(91)=295×35

f_1(n) = 2^(n+4)*3 - 5
Note that the times three means that this expression of of the form 3k - 5 which can be rewritten as 3(k-1)-2 which can again be rewritten as 3(k-2)+1.
Next, 3k+1 mod 3 = 1
So f_1(n) mod 3 = 1
Thus f_1^a(n) mod 3 = 1
f_2(a,b) = f_1^(2*f_2(a-1,b)+11)(1)
Note that f_1^(2*f_2(a-1,b)+11)(1) is also of the form f_1^a(n)
Thus f_2(a,b) mod 3 = 1

D(2,0,e1)

-->D1(2e1+8,3,1)>D1(2e1+8,0,f12(91))

e_1 mod 3 = 1; 2*1 + 8 = 10 --> 10 mod 3 = 1

D1(2e1+8,0,f12(91))

--> D1(1,0,f2(2e1+73,f12(91)))

e2=f2(2e1+73,f12(91))

D1(1,0,e3)

e2mod3=1

--> D1(2e2+7,3,1)>D1(2e2+7,0,f12(91))

2e_3 + 7

Modulus: 2 + 7 --> 9 mod 3 = 0

--> D1(0,0,f2(2e2+73,f12(91)))

e3=f2(2e2+73,f12(91))


D1(0,0,e3)

--> D(2e3+5,3,1)>D(2e3+5,0,f12(91))

e_3 mod 3 = 1; 2*1+5 = 7 --> 7 mod 3 = 1

--> D(1,0,f2(2e3+43,f12(91)))

e4=f2(2e3+43,f12(91))


D(1,0,e4)

--> halts with score 4e4+18.

This can be bounded by:

245<222(7.92×1028)<e4<σ<S<222(7.93×1028)