Multidimensional Turing Machine

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This is a work in progress.

A multidimensional Turing Machine is a Turing Machine that use a multidimensional tape instead. These Turing Machines have (2*dimension count) different moving directions, 2 each for 1 dimension.

Example: 1RB0UA_1DA0LB is a 2-dimensional Turing Machine, used L, R, U (Up), D (Down) 4 moving directions, and 1RB0FA_1DA0LC_1BC0UA is a 3-dimensional Turing Machine, used L, R, U, D, F (Front), B (Back) 6 moving directions.

BB_2D(n,m) = Maximum number of steps taken by a halting n-state, m-symbol 2D Turing machine starting from a blank (all 0) 2D tape, BB_3D(n,m) = Maximum number of steps taken by a halting n-state, m-symbol 3D Turing machine starting from a blank (all 0) 3D tape and BB_MD(n,m) = Maximum number of steps taken by a halting n-state, m-symbol multidimensional Turing machine starting from a blank (all 0) multidimensional tape (which uses at most n*m-1 dimensions).

Values

Note: Champions are not TNF form.

Domain Runtime Champion
BB_2D(2) >= 6 Same as BB(2)
BB_2D(3) >= 32 1DB1LC_0LC0RB_1UA1RZ
BB_2D(4) >= 4,632 1RB0DB_1UD1RC_0LA1UC_1LA1RZ
BB_2D(5) >= 25,772,988,638 1UB1RZ_1DC0LD_0RE0RD_1LA0LB_0UA0UB
BB_2D(2,3) >= 38 Same as BB(2,3)
Domain Score Champion
BB_2D(2) >= 4 Same as BB(2)
BB_2D(3) >= 11 1LC1RB_1DA1UB_1UB1RZ
BB_2D(4) >= 244 1RB0LA_1LD1DA_1DA1RZ_1LC1UD
BB_2D(5) >= 935,508,401 1UB1RZ_0RC1UD_1DE0LD_1UC1DD_1LD0RA
BB_2D(2,3) >= 10 1UB2LB0RA_1DA2UB1RZ

Tree Normal Form

TNF for multidimensional Turing Machine is same as TNF for 1D Turing Machine, except you can use multidimensional choice for transition. The choice will have additional restrictions:

  • The next direction of a transition may be any previously visited dimension or the next unvisited dimension.
  • If we are expanding the first transition of a new dimension, the direction must be positive for this dimension. (e.g. R, U, F).

External Links

https://github.com/GollyGang/ruletablerepository/wiki/TwoDimensionalTuringMachines