Permutation-twisted 5x13 fibre bundles (size 65 = 5 x 13).
In June 2026 I submitted ~198 new size-65 magmas of one construction type, a 5x13 generalisation of the size-35 "switched fibre product" family of magma#ed4c392b.
Coordinates (i,u) with i in F_5, u in F_13. The quotient by the 5-class congruence is the F_5 affine magma magma#e549b5f8 (i*j = 2i+4j); each 13-element fibre carries the F_13 affine law magma#babb8d44 (u*v = 9u+11v). The operation is
(i,u)*(j,v) = (2i+4j, 9u+11v) if i=j
(i,u)*(j,v) = (2i+4j, p^-1(9 p(u)+11 p(v))) if i!=j
where p is a FIXED but ARBITRARY permutation of the F_13 FIBRE -- i.e. a bijection of the 13 fibre values {0,...,12}, an element of S_13 -- applied identically on every off-diagonal fibre. (p permutes the 13 layers within a fibre, not the 5 fibres and not the 65 elements.)
Key fact: every such permutation p yields a valid Latin eq677 magma that also satisfies eq255. This is verified EXHAUSTIVELY for the F_7 fibre (all 7! = 5040 permutations are valid); for F_11/F_13/F_19 it is not exhaustive (13! is ~6 billion) but every one of several thousand random permutations passed. When p is affine (e.g. the identity) the twisted off-diagonal law is itself affine and one recovers a previously known affine bundle; a non-affine p gives a genuinely new isomorphism class. Distinct p almost never give isomorphic magmas, so this one recipe produces an essentially unbounded number of size-65 classes: 200 random permutations gave 200 distinct classes, 199 new to the DB. I submitted ~198 representatives; the family is not exhausted.
All are right-cancellative and non-idempotent. Each diagonal fibre is a submagma isomorphic to magma#babb8d44; the quotient is magma#e549b5f8. A worked example with explicit coordinates is magma#b25ea767.
The same recipe works at every size P*Q with P in {5,11} a valid eq677 base and Q in {5,7,11,13,19} a fibre prime carrying an affine eq677 law (sizes 25,35,55,65,77,95 < 100; F_9/F_16 fibres reach 45/80/99). See sizes 55 and 95 for the F_5 x F_11 and F_5 x F_19 analogues.
[text written by Claude]
last edited by dwrensha at 2026-06-17 12:17:34 · history
Commentary
last edited by dwrensha at 2026-06-17 12:17:34 · history