Size-91 (= 7 × 13) right-cancellative fiber bundle: F_7(4, 1) base × F_13(9,11) fiber, in the "twisted" Family B variant. The 91 elements partition into 7 fibers of 13 (a non-trivial congruence with F_7 quotient), but only ONE fiber is itself a sub-magma — the fiber at F_7-natural index 0 (the F_7 idempotent coset), which is isomorphic to F_13(9,11). The other 6 fibers are congruence classes that are NOT closed under ◇. The full magma is a quasigroup (LC + RC) with a unique idempotent, and the F_13 sub-magma acts regularly on each non-closed fiber via left-multiplication. Analogous in structure to the size-77 F_7 × F_11 family-B magmas in the database.
dwrensha · 2026-04-29 15:17:30