Skelet 10: Difference between revisions

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Mentioned Z(n) being in little-endian
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Linked base fibonacci to the wikipedia article about Zeckendorfs theorem
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== Behavior ==
== Behavior ==


Skelet 10 implements two base fibonacci counters, one on the right tape side and one on the left tape side. The TM halts if these counters become desynchronised.<ref name="bbchallenge 2025"/> The right side counter can be described by the following rules:<ref name="Sligocki">https://www.sligocki.com/2023/03/14/skelet-10.html</ref>
Skelet 10 implements two [https://en.wikipedia.org/wiki/Zeckendorf%27s_theorem base fibonacci] counters, one on the right tape side and one on the left tape side. The TM halts if these counters become desynchronised.<ref name="bbchallenge 2025"/> The right side counter can be described by the following rules:<ref name="Sligocki">https://www.sligocki.com/2023/03/14/skelet-10.html</ref>
<pre>
<pre>
A>  0 10^k 0 --> <D 0^2k  10
A>  0 10^k 0 --> <D 0^2k  10

Revision as of 13:47, 21 February 2026

1LC0LA_---0LC_0RD1LA_1LB1RE_1RD0RE (bbch), called Skelet #10, was one of Skelet's 43 holdouts and one of the last holdouts in BB(5). It is a double fibonacci counter. It is one of the few TMs to have required an individual proof of non-halting in Coq-BB5.[1]

Behavior

Skelet 10 implements two base fibonacci counters, one on the right tape side and one on the left tape side. The TM halts if these counters become desynchronised.[1] The right side counter can be described by the following rules:[2]

A>  0 10^k 0 --> <D 0^2k   10
B> 10 10^k 0 --> <D 0^2k+1 10

These rules are equivalent to the Zeckendorf increment rules in base fibonacci and can be restated as:[2]

Z(n) = 0 w ==> A> Z(n) --> <D Z(n+1)
Z(n) = 1 w ==> B> Z(n) --> <D Z(n+1)
Where Z(n) = 0 w means that the least-significant bit in Z(n) is 0 and Z(n) represents n in base fibonacci in the little-endian (least significant digit is on the left) representation.

The left side counter encodes base fibonacci differently and is also reversed, with the least-significant digit being on the right.[2]

See also

References