1RB3RB1LB---2RB 2LA1RA4LB2LA2RA: Difference between revisions

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Added Category:BB(2,5)
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Added proof by @dyuan01, improved structure, noted equivalence to 1RB3RA2LB1LB1RB_2LA2RA4LA1LA---.
 
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{{machine|1RB3RB1LB---2RB_2LA1RA4LB2LA2RA}}{{Stub}}
{{machine|1RB3RB1LB---2RB_2LA1RA4LB2LA2RA}}{{Stub}}
{{TM|1RB3RB1LB---2RB_2LA1RA4LB2LA2RA|undecided}} is a [[BB(2,5)]] machine whose behavior is suspected to be similar to [[Skelet 17]].
{{TM|1RB3RB1LB---2RB_2LA1RA4LB2LA2RA|undecided}} is a [[BB(2,5)]] machine whose behavior is similar to [[Skelet 17]]. [https://discord.com/channels/960643023006490684/1259770421046411285/1267650177389432913 A proof was given by Daniel Yuan (@dyuan01) of the machine's nonhalting on July 30th 2024.] {{TM|1RB3RA2LB1LB1RB_2LA2RA4LA1LA---|undecided}} is equivalent to this machine.
 
Analysis shared by Daniel Yuan (@dyuan01) on Discord, [https://discord.com/channels/960643023006490684/1084047886494470185/1251145215461560391 on June 14th 2024]:


=== Analysis shared by Daniel Yuan (@dyuan01) on Discord, [https://discord.com/channels/960643023006490684/1084047886494470185/1251145215461560391 on June 14th 2024]: ===
I just checked whenever the beaver reaches the 1 on the left side, and calculated the tape for when it next reaches the left side. It would be nice if someone can verify these rules.
I just checked whenever the beaver reaches the 1 on the left side, and calculated the tape for when it next reaches the left side. It would be nice if someone can verify these rules.


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[2n+1, 2a, 2b, …, 2m+1, x, …] -> [2n, 2a, 2b, …, 2m+1, x+1, …]
[2n+1, 2a, 2b, …, 2m+1, x, …] -> [2n, 2a, 2b, …, 2m+1, x+1, …]
[2n+2, a, b, …] -> [2n+1, a+1, b, …]
[2n+2, a, b, …] -> [2n+1, a+1, b, …]
</pre>


And you should start at [1, 1].
And you should start at [1, 1].
</pre>


== Review ==
== Review ==
Matthew House (@LegionMammal978) reviewed the above analysis on [https://discord.com/channels/960643023006490684/1084047886494470185/1251210996224364766 June 14th 2024] and agrees with it.
Matthew House (@LegionMammal978) reviewed the above analysis on [https://discord.com/channels/960643023006490684/1084047886494470185/1251210996224364766 June 14th 2024] and agrees with it.
 
The proof given by @dyuan01 is not yet verified.
[[Category:BB(2,5)]]
[[Category:BB(2,5)]]

Latest revision as of 17:46, 25 October 2025

1RB3RB1LB---2RB_2LA1RA4LB2LA2RA (bbch) is a BB(2,5) machine whose behavior is similar to Skelet 17. A proof was given by Daniel Yuan (@dyuan01) of the machine's nonhalting on July 30th 2024. 1RB3RA2LB1LB1RB_2LA2RA4LA1LA--- (bbch) is equivalent to this machine.

Analysis shared by Daniel Yuan (@dyuan01) on Discord, on June 14th 2024:

I just checked whenever the beaver reaches the 1 on the left side, and calculated the tape for when it next reaches the left side. It would be nice if someone can verify these rules.

[x, y, z] := 1 <B 4^x 12 4^y 12 4^z

[0, a, b, …] -> [a+3, b, …]
[2n+1, 2a, 2b, …, 0] -> Halt 
[2n+1, 2a, 2b, …, 2m+2] -> [2n, 2a, 2b, …, 2m+2, 0]
[2n+1, 2a, 2b, …, 2m+1] -> [2n, 2a, 2b, …, 2m+1, 1]
[2n+1, 2a, 2b, …, 2m+1, x, …] -> [2n, 2a, 2b, …, 2m+1, x+1, …]
[2n+2, a, b, …] -> [2n+1, a+1, b, …]

And you should start at [1, 1].

Review

Matthew House (@LegionMammal978) reviewed the above analysis on June 14th 2024 and agrees with it.

The proof given by @dyuan01 is not yet verified.