出典:Wikipedia
出典:『Wikipedia』 (2011/02/20 10:54 UTC 版)
The star height problem in formal language theory is the question whether all regular languages can be expressed using regular expressions of limited star height, i.e. with a limited nesting depth of Kleene stars. Specifically, is a nesting depth greater than 1 required? If so, is there an algorithm to determine how many are required? The problem was raised by .