Lists of finite lattices (graded, n=21 elements, c>2 coatoms)

List of vertically indecomposable graded lattices of 21 elements and 3...19 coatoms, in xz-compressed digraph6 format.一份包含21个元素、3至19个上原子（coatoms）的垂直不可分解分次格的列表，采用xz压缩的digraph6格式存储。