This shell contains applications which are essential for problems involving group-subgroup relations between space groups. Given the space group types of G and H and their index, the program [http://www.cryst.ehu.es/cryst/subgroupgraph.html SUBGROUPGRAPH] provides graphs of maximal subgroups for a group-subgroup pair G > H, all the different subgroups H and their distribution into conjugacy classes. The Wyckoff position splitting rules for a group-subgroup  pair are calculated by the program [http://www.cryst.ehu.es/cryst/wpsplit.html WYCKSPLIT].