Skelet - Revision history

Polygon: linked BB(4)

2026-02-21T12:24:19Z

linked BB(4)

← Older revision		Revision as of 12:24, 21 February 2026
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	In 2003, he announced his results on his [https://skelet.ludost.net/bb/ webpage] in which he shared his code '''bbfind''' (a 6000 line Pascal program) which he claimed enumerated 150M 5-state TMs and reduced them down to 164 [[holdouts]] (he called them "nonregular machines"). After manually analyzing these 164 nonregular machines he reduced it to 43 holdouts which he called "hardly nonregular" (HNR) which were not solvable by his program nor by hand. These 43 HNR TMs became famous examples of hard TMs to prove and these TMs began to be named by their place on this list (such as [[Skelet 1]] and [[Skelet 17]]).		In 2003, he announced his results on his [https://skelet.ludost.net/bb/ webpage] in which he shared his code '''bbfind''' (a 6000 line Pascal program) which he claimed enumerated 150M 5-state TMs and reduced them down to 164 [[holdouts]] (he called them "nonregular machines"). After manually analyzing these 164 nonregular machines he reduced it to 43 holdouts which he called "hardly nonregular" (HNR) which were not solvable by his program nor by hand. These 43 HNR TMs became famous examples of hard TMs to prove and these TMs began to be named by their place on this list (such as [[Skelet 1]] and [[Skelet 17]]).

	Due to the length and lack of comments in bbfind's source code, Skelet's work is not believed to have been independently verified.<ref>"[https://bbchallenge.org/story#skelets-43-undecided-machines Story]" (section "Skelet's 43 undecided machines").</ref> It is now known that all 43 of these holdouts do not halt. Other work done in bbfind includes computing the correct value of BB(4) and for "RTM(5)" (the set of all "[https://skelet.ludost.net/bb/RTM.htm Reversal Turing Machines]").		Due to the length and lack of comments in bbfind's source code, Skelet's work is not believed to have been independently verified.<ref>"[https://bbchallenge.org/story#skelets-43-undecided-machines Story]" (section "Skelet's 43 undecided machines").</ref> It is now known that all 43 of these holdouts do not halt. Other work done in bbfind includes computing the correct value of [[BB(4)]] and for "RTM(5)" (the set of all "[https://skelet.ludost.net/bb/RTM.htm Reversal Turing Machines]").

	== Skelet's 43 HNR TMs ==		== Skelet's 43 HNR TMs ==

Polygon: Added category:people

2025-12-04T17:51:26Z

Added category:people

← Older revision		Revision as of 17:51, 4 December 2025
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	<references/>		<references/>
	[[Category:BB(5)]]		[[Category:BB(5)]]
			[[Category:People]]

Polygon: Added Category:BB(5)

2025-09-27T16:43:13Z

Added Category:BB(5)

← Older revision		Revision as of 16:43, 27 September 2025
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	== References ==		== References ==
	<references/>		<references/>
			[[Category:BB(5)]]

Int-y1: fix sort

2025-07-09T03:07:22Z

fix sort

← Older revision		Revision as of 03:07, 9 July 2025
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	!Offset		!Offset
	\|-		\|-
	\| 1 \|\| <math>\approx 5.42 \times 10^{51}</math> \|\| 8468569863 \|\| -107917		\| 1 \|\|data-sort-value="5.42e51"\| <math>\approx 5.42 \times 10^{51}</math> \|\| 8468569863 \|\| -107917
	\|-		\|-
	\| 2 \|\| 15055 \|\| 4328 \|\| 74		\| 2 \|\| 15055 \|\| 4328 \|\| 74

Int-y1: not a stub anymore

2025-07-09T02:06:23Z

not a stub anymore

← Older revision		Revision as of 02:06, 9 July 2025
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	== References ==		== References ==
	<references/>		<references/>

	~~[[Category:Stub]]~~

Sligocki: /* Translated Cycler Periods */

2025-05-21T02:11:09Z

Translated Cycler Periods

← Older revision		Revision as of 02:11, 21 May 2025
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	\| 25 \|\| 6354 \|\| 589 \|\| 23		\| 25 \|\| 6354 \|\| 589 \|\| 23
	\|}		\|}
	While Skelet #1 is technically a Translated Cycler, it requires specialized acceleration to prove this. Whereas all the other cyclers can be demonstrated by ~~direction~~ simulation.		While Skelet #1 is technically a Translated Cycler, it requires specialized acceleration to prove this. Whereas all the other cyclers can be demonstrated by direct simulation.

	This list is not necessarily exhaustive, it is possible that some of the other Skelet machines are also Translated Cyclers with very large start step or periods, but were proven infinite using a [[Closed Set]] method.		This list is not necessarily exhaustive, it is possible that some of the other Skelet machines are also Translated Cyclers with very large start step or periods, but were proven infinite using a [[Closed Set]] method.

Sligocki: /* Translated Cycler Periods */ Add caveat about there potentially being other TCs.

2025-05-21T02:03:14Z

Translated Cycler Periods: Add caveat about there potentially being other TCs.

← Older revision		Revision as of 02:03, 21 May 2025
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	=== Translated Cycler Periods ===		=== Translated Cycler Periods ===
	Several of Skelet's holdouts were translated cyclers, here are the parameters for them. Start step is the earliest step that the cycle starts at. Period is the step count per cycle. Offset is the translation shift along tape each period (positive to the right, negative to the left)~~. While Skelet #1 is technically a Translated Cycler, it requires specialized acceleration to prove this. Whereas all the other cyclers can be demonstrated by direction simulation~~.		Several of Skelet's holdouts were translated cyclers, here are the parameters for them. Start step is the earliest step that the cycle starts at. Period is the step count per cycle. Offset is the translation shift along tape each period (positive to the right, negative to the left).

	{\| class="wikitable sortable"		{\| class="wikitable sortable"
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	\| 25 \|\| 6354 \|\| 589 \|\| 23		\| 25 \|\| 6354 \|\| 589 \|\| 23
	\|}		\|}
			While Skelet #1 is technically a Translated Cycler, it requires specialized acceleration to prove this. Whereas all the other cyclers can be demonstrated by direction simulation.

			This list is not necessarily exhaustive, it is possible that some of the other Skelet machines are also Translated Cyclers with very large start step or periods, but were proven infinite using a [[Closed Set]] method.

	== References ==		== References ==

Sligocki: /* Skelet's 43 HNR TMs */ Add table of TC periods, etc.

2025-05-21T01:59:27Z

Skelet's 43 HNR TMs: Add table of TC periods, etc.

@@ Line 232: / Line 232: @@
+|
 |TABLE_BASED_NG_7_10
 |}

Peacemaker II: Undo revision 1985 by Peacemaker II (talk)

2025-05-21T00:22:37Z

Undo revision 1985 by Peacemaker II (talk)

← Older revision		Revision as of 00:22, 21 May 2025
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	!Proof by [[Coq-BB5]]		!Proof by [[Coq-BB5]]
	\|-		\|-
	\|~~[[Skelet~~ 1~~\|1]]~~		\|1
	\|{{TM\|1LC1LE_---1LD_1RD0LD_1LA1RE_0LB0RC}}		\|{{TM\|1LC1LE_---1LD_1RD0LD_1LA1RE_0LB0RC}}
	\|[[Translated cycler]]<ref>https://www.sligocki.com/2023/03/13/skelet-1-infinite.html</ref>		\|[[Translated cycler]]<ref>https://www.sligocki.com/2023/03/13/skelet-1-infinite.html</ref>
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	\|TABLE_BASED_DNV_11		\|TABLE_BASED_DNV_11
	\|-		\|-
	\|~~[[Skelet~~ 17~~\|17]]~~		\|17
	\|{{TM\|1LB---_0RC1LE_0RD1RC_1LA1RB_0LB0LA}}		\|{{TM\|1LB---_0RC1LE_0RD1RC_1LA1RB_0LB0LA}}
	\|[[Dekaheptoid]]		\|[[Dekaheptoid]]

Peacemaker II at 00:20, 21 May 2025

2025-05-21T00:20:30Z

← Older revision		Revision as of 00:20, 21 May 2025
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	!Proof by [[Coq-BB5]]		!Proof by [[Coq-BB5]]
	\|-		\|-
	\|1		\|[[Skelet 1\|1]]
	\|{{TM\|1LC1LE_---1LD_1RD0LD_1LA1RE_0LB0RC}}		\|{{TM\|1LC1LE_---1LD_1RD0LD_1LA1RE_0LB0RC}}
	\|[[Translated cycler]]<ref>https://www.sligocki.com/2023/03/13/skelet-1-infinite.html</ref>		\|[[Translated cycler]]<ref>https://www.sligocki.com/2023/03/13/skelet-1-infinite.html</ref>
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	\|TABLE_BASED_DNV_11		\|TABLE_BASED_DNV_11
	\|-		\|-
	\|17		\|[[Skelet 17\|17]]
	\|{{TM\|1LB---_0RC1LE_0RD1RC_1LA1RB_0LB0LA}}		\|{{TM\|1LB---_0RC1LE_0RD1RC_1LA1RB_0LB0LA}}
	\|[[Dekaheptoid]]		\|[[Dekaheptoid]]