2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66619Entringer, Jackson, and Schatz conjectured in 1974 that every infinite cubefree binary word contains arbitrarily long squares. In this paper we show this conjecture is false: there exist infinite cubefree binary words avoiding all squares xx with |x| >= 4, and the number 4 is best possible. However, the Entringer-Jackson-Schatz conjecture is true if "cubefree" is replaced with "overlap-free".PLEASE NOTE: After this paper was prepared, we learned that all our results appeared (albeit with different proofs) in a paper of F. M. Dekking, On repetitions of blocks in binary sequences, J. Combin. Theory Ser. A 20 (1976), 292--299CombinatoricsDiscrete Mathematics68R15text