We characterize proximality of multidimensional B-free systems in the case of number fields and lattices in Z m , m ě 2.1. Introduction. In this paper, we study proximality of generalizations of B-free systems [1,10]. Let B Ď N. Integers with no factors in B are called B-free numbers and are denoted by F B . Such sets were studied already in the 30's by Behrend, Chowla, Davenport, Erdős, Schur and others. Note that, if S " tp 2 : p is primeu then 1 F S " µ 2 , where µ : Z Ñ C is the Möbius function given by the following formula:The dynamical approach to study B-free systems is rather new. In 2010, Sarnak in his seminal paper [17] proposed to study the dynamical systems determined by µ and µ 2 . In either case, we consider the closure X η of the orbit of η " µ P t´1, 0, 1u Z or η " µ 2 P t0, 1u Z under the left shift S. The dynamics of pX µ , Sq is complicated and there are many open questions related to it. The system pX µ 2 , Sq (called squarefree system) which is a topological factor of pX µ , Sq via the map px n q nPZ Þ Ñ px 2 n q nPZ is simpler to study. Similarly, given B Ď N, taking the closure of the orbit of η " 1 F B P t0, 1u Z under the left shift, yields a B-free system. At first, B-free systems were studied in the Erdős case, i.e., for B infinite, pairwise coprime, withLet G be a countable abelian group. Recall that proper subgroups H 1 , H 2 Ď G are said to be coprime whenever H 1`H2 " G. Let pT g q gPG be an action of G by homeomorphisms on a compact metric space pX, Dq. The pair pX, pT g q gPG q is called a topological dynamical system. Two complementary, basic concepts of topological dynamics are distality and proximality. Recall that a pair px, yq of points from X is called distal if lim inf gÑ8 DpT g x, T g yq ą 0, otherwise px, yq is called proximal. If any pair of distinct points in X is distal (respectively, proximal) then the