Mirror invariance conjecture for the Thue–Morse two-block language

Let x(00)x^{(00)} be the fixed point of the Thue–Morse two-block substitution, and let L\scTML_{\rm\sc TM} be the language of all finite words occurring in x(00)x^{(00)}. A set of binary words is mirror invariant if, whenever it contains w1wmw_1\dots w_m, it also contains (1w1)(1wm)(1-w_1)\dots(1-w_m). Mirror invariance conjecture. The language L\scTML_{\rm\sc TM} is mirror invariant. This is contrasted with the fact that the language is not reversal invariant; proving mirror invariance is difficult because mirror images of occurring words may first appear only after many substitution iterations.

Sources & referencesView supporting material

Primary source

Michel Dekking and Mike Keane, “Two-block substitutions and morphic words”, arXiv:2202.13548 (2023).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.