English

Binary equality sets are generated by two words

Formal Languages and Automata Theory 2012-09-19 v1 Combinatorics

Abstract

We show that the equality language of two non-periodic binary morphisms is generated by at most two words. If its rank is two, then the generators start (and end) with different letters. This in particular implies that any binary language has a test set of cardinality at most two.

Cite

@article{arxiv.1209.4061,
  title  = {Binary equality sets are generated by two words},
  author = {Štěpán Holub},
  journal= {arXiv preprint arXiv:1209.4061},
  year   = {2012}
}

Comments

Thoroughly revised version of a journal publication

R2 v1 2026-06-21T22:07:30.398Z