Cut lattices and equiangular lines (Q1911836)

The authors consider relations between cut lattices \(L_n\) and systems of equiangular lines (i.e., sets of lines where the acute angle between any pair is the same). They investigate cut-sublattices of \(L_n\) generated by subsets of cuts. For even \(n\), \(L_n\) is generated by an odd system. Equiangular line systems related to \(L_n\) are described, and a sequence of symmetric 2-designs, also related to these line systems, is defined. Further on, certain relations to Hadamard matrices are presented.