bibkey: bulgakovafridscanvic2022sierpinski authors: D. Bulgakova, A. Frid, and J. Scanvic year: 2022 title: “Prefix palindromic length of the Sierpinski word” doi: null url: https://arxiv.org/abs/2201.09556v3 claim: “The abstract recalls the conjectured failure of 2-regularity for period-doubling prefix palindromic length; the paper treats the Sierpinski word.” strata_touched:

• D5/S1/Words/Palindromes/PeriodDoubling/PrefixPalindromicLengthNotAutomatic license: citation-only triage: anchor

Sierpinski prefix palindromic length

The abstract on printed page 1 says:

A more recent conjecture concerns the prefix palindromic length of the period doubling word: it seems that it is not 2-regular, and if it is true, this would give a rare if not unique example of a non-regular function of a 2-automatic word.

The paper gives a complete description of the Sierpinski word’s prefix palindromic length. Its recalled period-doubling conjecture is literature context, not a proof of that conjecture.