Lazy Beaver: Difference between revisions

From BusyBeaverWiki
Jump to navigation Jump to search
m Right align table.
Δ⁵ (talk | contribs)
m added context
 
(2 intermediate revisions by one other user not shown)
Line 2: Line 2:


LB(n, m) is the smallest k > 0 such that no n-state, m-symbol [[Turing machine]] halts in exactly k steps.
LB(n, m) is the smallest k > 0 such that no n-state, m-symbol [[Turing machine]] halts in exactly k steps.
Unlike the variant that uses score, LB is computable. This is because the number of steps taken before halting is a syntactic property, so Rice's theorem does not apply.


== Computed Values ==
== Computed Values ==
Values found by Terry and [[User:Sligocki|Shawn Ligocki]] in 2021:
Values found by Terry and [[User:Sligocki|Shawn Ligocki]] in 2021:
{| class="wikitable" style="text-align: right;"
{| class="wikitable" style="text-align: right;"
|+
|+LB(n, m)
!
!
! colspan="5" |States
|-
|-
!
!
!
!2-state
!2
!3-state
!3
!4-state
!4
!5-state
!5
!6-state
!6
|-
|-
| rowspan="5" |Symbols
!2-symbol
|2
|7
|7
|22
|22
Line 27: Line 24:
|8,407
|8,407
|-
|-
|3
!3-symbol
|23
|23
|351
|351
Line 34: Line 31:
|
|
|-
|-
|4
!4-symbol
|93
|93
|242,789
|242,789
Line 41: Line 38:
|
|
|-
|-
|5
!5-symbol
|956
|956
|
|
Line 48: Line 45:
|
|
|-
|-
|6
!6-symbol
|33,851
|33,851
|
|
Line 60: Line 57:
[[category:Functions]]
[[category:Functions]]


* https://oeis.org/A337805
* https://oeis.org/A337805: LB(n, 2)

Latest revision as of 04:06, 9 October 2026

The Lazy Beaver function is a computable variation of the Busy Beaver function defined by Scott Aaronson in his 2020 review.

LB(n, m) is the smallest k > 0 such that no n-state, m-symbol Turing machine halts in exactly k steps.

Unlike the variant that uses score, LB is computable. This is because the number of steps taken before halting is a syntactic property, so Rice's theorem does not apply.

Computed Values

Values found by Terry and Shawn Ligocki in 2021:

LB(n, m)
2-state 3-state 4-state 5-state 6-state
2-symbol 7 22 72 427 8,407
3-symbol 23 351 189,270
4-symbol 93 242,789
5-symbol 956
6-symbol 33,851

See Also