MINIMAL EXPANSIONS OF SEMILATTICES
Peter Jipsen, Andrzej Kisielewicz · International Journal of Algebra and Computation · 2004
We determine the minimal extension of the sequence . This completes and extends the work of Koh, started in 1970, and solves Problem 15 in the survey on pn-sequences and free spectra [4]. The results involve the investigation of some minimal expansions of semilattices.