Size-49 (= 7²) right-cancellative fiber bundle: F_7(4, 1) base × F_7(4, 1) fiber. The 49 elements partition into 7 fibers of 7 (an F_7-quotient congruence). One fiber is itself a sub-magma — the fiber at the F_7-idempotent coset, ≅ F_7(4, 1). In addition there is exactly one extra 7-element sub-magma, a transversal that hits each fiber in exactly one element. The 2 size-7 sub-magmas (1 closed fiber + 1 transversal) form a small AG(2,7)-pencil fragment. Quasigroup (LC + RC) with a unique idempotent.
dwrensha · 2026-04-29 15:53:17