Equation 677 Database

Size 961

14 isomorphism classes.

magma 3259f7fb of size 961 magma ecd0e67d of size 961 magma bbe4461e of size 961 magma 1335ae05 of size 961 magma 85c84627 of size 961 magma 7ff29f81 of size 961 magma 67e60649 of size 961 magma 896897f8 of size 961 magma ba90950a of size 961 magma 2b8e3c08 of size 961 magma 3c1d2230 of size 961 magma 5f44e78d of size 961 magma fc322ba7 of size 961 magma 39810531 of size 961

Commentary

Size 961 = 31² admits several distinct families of Eq 677 magmas. 13 entries are currently in the DB; all satisfy Eq 255. All known constructions use one of two carriers: • F_961 = GF(31²) (additive group (Z/31)²) — for the line magmas and the near-field-style magma • A direct product G × M with G abelian — for the Tao G × M fiber bundles Family A: AG(2, 31) constant-α line magmas (5 magmas, right-cancellative, idempotent). The 992 = 32 × 31 size-31 sub-magmas are exactly the lines of the affine plane AG(2, 31); every pair of distinct points lies on a unique line. Each line is the F_31 linear magma with parameter α, the same α for ALL 32 parallel classes. Equivalently, the magma is the medial direct product F_31(α) × F_31(α). The 4 valid α-values are the primitive 10th roots of unity mod 31 = roots of Φ_10(x) = x⁴ − x³ + x² − x + 1, namely {15, 23, 27, 29}; all four are present: • α = 15: magma#2b8e3c08 • α = 23: magma#5f44e78d • α = 27: magma#ba90950a • α = 29: magma#fc322ba7 Family B: 16-coset Tao-Type-II piecewise on F_961 (1 magma, right-cancellative, idempotent). magma#3c1d2230. Carrier F_961 = GF(31²) additively; the operation x ◇ y = x + f(y − x) has f with cycle structure (1, 60¹⁶) — 16 cosets of an order-60 subgroup of F_961* (which has order 960 = 16 × 60). f is axis-additive over (Z/31)² but NOT globally F_31-linear (a fingerprint of near-field multiplication). Since 31 is not in the Zassenhaus exceptional near-field list {5, 7, 11, 23, 29, 59}, this is presumably a Dickson near-field construction with the order-2 Frobenius. The 2-generated sub-magmas already span all 961 points (no AG(2, 31) line sub-structure here). Family C: Tao G × M fiber-bundle constructions (8 magmas, non-right-cancellative, idempotent). All 8 are dwrensha submissions of the form Tao(F_31, β=2) × F_31(ζ, ω) for various (ζ, ω) parameters (ζ ∈ {2, 4, 8, 16}, ω ∈ {5, 25}, giving 8 combinations). An abelian base group acts on a fiber via a 2-cocycle; the resulting magma is non-right-cancellative because the fiber action allows column collapses while preserving left bijectivity. Examples: magma#3259f7fb, magma#ecd0e67d, magma#bbe4461e, magma#1335ae05, magma#85c8462b, magma#7ff29f81, magma#67e60649, magma#896897f8. The five Family-A magmas exhaust the constant-α line magmas at size 961 (one per valid α). Non-constant-α AG(2, 31) line magmas (where different parallel classes use different α-values, analogous to many size-121 entries) are NOT yet represented at size 961; by Burnside, the orbit count of α-colorings of 32 parallel classes under PGL(2, 31) would be in the tens of thousands. Display reorders for the four b-reinke entries have been set: Family-A magmas use a 2D AG-coordinate layout (rows = lines of one parallel class C_h, columns = lines of another class C_v), showing clean 31 × 31 block structure; the Family-B magma uses an orbit-of-0 layout under two commuting order-31 fix-free automorphisms (the hidden (Z/31)² additive translations), giving a fully translation-invariant Cayley table. [text written by Claude]

last edited by dwrensha at 2026-05-14 21:35:14 · history