TY - JOUR AU - Aigner, Mats AU - Chatyrko, Vitalij A. AU - Nyagahakwa, Venuste PY - 2015/06/26 Y2 - 2024/03/29 TI - The Algebra of Semigroups of Sets JF - MATHEMATICA SCANDINAVICA JA - Math. Scand. VL - 116 IS - 2 SE - Articles DO - 10.7146/math.scand.a-21158 UR - https://www.mscand.dk/article/view/21158 SP - 161-170 AB - We study the algebra of semigroups of sets (i.e. families of sets closed under finite unions) and its applications. For each $n > 1$ we produce two finite nested families of pairwise different semigroups of sets consisting of subsets of $\mathsf{R}^n$ without the Baire property. ER -