Groups whose commutator structure agrees: there are isomorphisms G/Z(G) → H/Z(H) and G′ → H′ carrying one commutator map to the other. The class spans orders — G × A is isoclinic to G for every abelian A.
Stem order 18: every member's order is a multiple of it, and the members attaining it — the stem groups — are marked ◆.
1,024 groups of the catalog are in this class; the 1,017 with an abelian direct factor are hidden.
| group | order | × stem | |
|---|---|---|---|
| D9 | 18 | ×1 | ◆ stem |
| Dic9 | 36 | ×2 | |
| C9⋊C8 | 72 | ×4 | |
| C9⋊C16 | 144 | ×8 | |
| C9⋊C32 | 288 | ×16 | |
| C9⋊C64 | 576 | ×32 | |
| C9⋊C128 | 1,152 | ×64 |
The class itself is infinite — G × A is isoclinic to G for every abelian A, and there are abelian groups of every order — so a table shows the part of it the catalog names, never the whole.