Busy Beaver
Busy Beaver
A busy beaver is a Turing machine that, when provided with a blank tape, does a lot of work. Formally, it is an -state -color Turing machine started on an initially blank tape that writes a maximum number of 1s or moves the head a maximum number before halting. This Demonstration shows most of the known values of historical and current busy beaver champions as discovered by several people over the last four decades. There are known values up to four states for two-color machines and explicit constructions give exact or lower bounds for other state and color pairs.
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