Delone sets in $\mathbb R^3$ with $2R$-regularity conditions

A regular system is the orbit of a point with respect to a crystallographic group. The central problem of the local theory of regular systems is to determine the value of the regularity radius, i.e., the radius of neighborhoods/clusters whose identity in a Delone $(r,R)$‑set guarantees its regularity. In this paper, conditions are described under which the regularity of a Delone set in three-dimensional Euclidean space follows from the pairwise congruence of small clusters of radius $2R$. Combined with the analysis of one particular case, this result also implies the proof of the "$10R$-theorem," which states that the congruence of clusters of radius $10R$ in a Delone set implies the regularity of this set.