5-state busy beaver winner: Difference between revisions
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(Add Michel version of formula (which I think is much simpler).) |
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The 5-state busy beaver champion (and winner!) is: [https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA&status=halt https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA]. It was found by Heiner Marxen and Jürgen Buntrock in 1989<ref>H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html</ref>. The machine halts after 47,176,870 steps and with 4098 1's on the tape, showing that <math>BB(5) \ge 47,176,870</math> and <math>\Sigma(5) \ge 4098</math>. | The 5-state busy beaver champion (and winner!) is: [https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA&status=halt https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA]. It was found by Heiner Marxen and Jürgen Buntrock in 1989<ref>H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html</ref>. The machine halts after 47,176,870 steps and with 4098 1's on the tape, showing that <math>BB(5) \ge 47,176,870</math> and <math>\Sigma(5) \ge 4098</math>. | ||
== Behavior == | |||
This machine repeatedly applies the following map, starting with <math>x = 0</math><ref>Aaronson, S. (2020). The Busy Beaver Frontier. Page 10-11. https://www.scottaaronson.com/papers/bb.pdf</ref>: | This machine repeatedly applies the following map, starting with <math>x = 0</math><ref>Aaronson, S. (2020). The Busy Beaver Frontier. Page 10-11. https://www.scottaaronson.com/papers/bb.pdf</ref>: | ||
<math display="block">\begin{align} | <math display="block">\begin{align} | ||
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g(x) & \to \frac{5x+22}{3} && \text{if }x \equiv 1 \pmod{3} \\ | g(x) & \to \frac{5x+22}{3} && \text{if }x \equiv 1 \pmod{3} \\ | ||
g(x) & \to \text{HALT} && \text{if }x \equiv 2 \pmod{3} | g(x) & \to \text{HALT} && \text{if }x \equiv 2 \pmod{3} | ||
\end{align}</math>which can alternatively be written as<ref>Pascal Michel. Behavior of busy beavers.https://bbchallenge.org/~pascal.michel/beh#tm52a</ref>: | |||
<math display="block">\begin{align} | |||
g(3k) & \to 5k+6 \\ | |||
g(3k+1) & \to 5k+9 \\ | |||
g(3k+2) & \to \text{HALT} \\ | |||
\end{align}</math> | \end{align}</math> | ||
Revision as of 03:03, 10 July 2024
The 5-state busy beaver champion (and winner!) is: https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA. It was found by Heiner Marxen and Jürgen Buntrock in 1989[1]. The machine halts after 47,176,870 steps and with 4098 1's on the tape, showing that and .
Behavior
This machine repeatedly applies the following map, starting with [2]:
which can alternatively be written as[3]:
The full orbit from is:
- ↑ H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html
- ↑ Aaronson, S. (2020). The Busy Beaver Frontier. Page 10-11. https://www.scottaaronson.com/papers/bb.pdf
- ↑ Pascal Michel. Behavior of busy beavers.https://bbchallenge.org/~pascal.michel/beh#tm52a