Last modified: April 4, 2018

Credit: Thanks to Edwin van Dam, Akihiro Munemasa, Misha Muzychuk and Jason Williford for their help with this data.

UPDATE: This data is outdated. Please refer instead to Williford's tables, which are up to date for d=3 (primitive) and d=4,5 (Q-bipartite).

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NOTE: In this table, we have not yet entered all schemes which are metric or duals of metric schemes. There is also an infinite family of Q-bipartite doubles of a certain family of Hermitian forms dual polar spaces. These have unbounded class number d and are described on p315 of the book by Bannai and Ito. So far, only one from this family appears in our table.

Cometric Schemes

d |X| Krein array m1 Cosines Prop. Description/Reference
3 classes
3 wv {v-1,(w-1)(s(v-2)+2k-v)/ws, 1;   1, (s(v-2)+2k-v)/ws, v-1}
s2 = k - λ
v-1 (1,   (v-k)/s(v-1),   -1/(v-1),   -k/s(v-1)   ) Q-antip. linked systems of symmetric designs
3 66 { 10, 242/27, 11/5;   1, 55/27, 44/5 } 10 ( 1,   4/15,   -1/10,   -7/15 ) prim. block scheme of 4-(11,5,1) Witt design
3 91 { 12, 338/35, 39/25;   1, 312/175, 39/5 } 12 (1,   7/20,   2/15,   -3/10) prim. (?) van Dam open case
3 99 { 14, 108/11, 15/4;   1, 24/11, 45/4 } 14 (1,   5/14,   -1/14,   -2/7 ) prim. (?) van Dam open case
3 759 { 23, 945/44, 1587/80;   1, 345/176, 207/20 } 23 (1,   1/4,   -1/8,   -1/2) prim. block scheme of 5-(24,8,1) Witt design
3 2025 {22,21,625/33;   1, 11/6, 30/11} 22 (1,  7/22,  -1/44,  -4/11) prim. Derived design from Leech lattice
3 4324 { 46, 77315/1782 , 24863/847;   1, 37835/19602 , 2162/231 } 46 (1,   19/66,   5/99,   -37/198 ) prim. block scheme of a 4-(47,11,48) design (QR code)
3 98280 {299, 1800/7, 4563/20;   1, 156/35, 195/4} 299 (1,   5/23,  1/46,  -1/23) prim. antipodal quotient of Leech lattice configuration
4 classes
4 2wd { d, d-1, d(w-1)/w, 1;   1, d/w, d-1, d } d (1,   d-1/2,   0,   -d-1/2,   -1) Q-bip.
Q-antip.
mutually unbiased bases (MUBs) in Rd
4 24 {4,3,8/3,1;   1, 4/3, 3, 4} 4 (1,   1/2,   0,   -1/2,   -1) Q-bip.
Q-antip.
24-cell , sample set of MUBs
4 72 {6, 5, 9/2, 3;   1, 3/2, 3, 6} 6 (1,   1/2,   0,   -1/2,   -1) Q-bip. shortest vectors of E6 lattice
4 126 {7, 6, 49/9, 35/8;   1, 14/9, 21/8, 7} 7 (1,   1/2,   0,   -1/2,   -1) Q-bip. shortest vectors of E7 lattice
4 132 { 11, 10, 242/27, 11/5;   1, 55/27, 44/5, 11 } 11 ( 1,   1/3,   0,   -1/3,   -1) Q-bip. block scheme of 5-(12,6,1) Witt design
extended Q-bipartite double of Ex. d3v66m10
4 150 { 21, 16, 8, 1;   1, 4, 16, 21 } 21 ( 1,   1/3,   1/21,   -1/7,   -3/7) Q-antip. Higman's ULS-SRD from U3(5)
(3 linked copies of the
Hoffman-Singleton graph)
4 162 { 20, 18, 3, 1;   1, 3, 18, 20 } 20 (1,   1/4,   1/10,   -1/5,   -7/20) Q-antip. dismantle dual scheme of coset graph of shortened ternary Golay code
4 168 { 20, 49/3, 56/9, 1;   1, 28/9, 49/3, 20 } 20 ( 1,   3/10,   1/15,   -1/6,   -2/5) Q-antip. Higman's ULS-SRD from L3(4)
(3 linked copies of the
Gewirtz graph)
4 240 {8,7,32/5,6;   1,8/5,2,8} 8 (1,   1/2,   0,   -1/2,   -1) Q-bip. shortest vectors of E8 lattice
4 512 { 16, 15, 128/9, 8;   1, 16/9, 8, 16 } 16 (1,   1/3,   0,   -1/3,   -1) Q-bip. shortest vectors of lattice OBW16 (Martinet)
4 2576 { 23, 22, 2645/126, 207/11;   1, 253/126, 46/11, 23 } 23 (1,   1/3,   0,   -1/3,   -1) Q-bip. block scheme of 5-(24,12,48) design (Golay code)
4 2816 {22, 21, 121/6, 55/3;   1, 11/6, 11/3, 22} 22 (1,   1/3,   0,   -1/3,   -1) Q-bip. 2nd derived design of Leech lattice
4 4224 {252, 605/3, 88/3, 1;   1, 44/3, 605/3, 252} 252 ( 1,   3/14,   13/189,   -1/54,   -1/21) Q-antip. Higman's ULS-SRD from U6(2)
(3 orbits of points of type 222-2233 in Leech lattice)
4 4600 {23, 22, 529/25, 184/9;   1, 46/25, 23/9, 23 } 23 (1,   1/3,   0,   -1/3,   -1) Q-bip. Derived design of Leech lattice
4 7128 { 22, 21, 121/6, 2187/125;   1, 11/6, 363/125, 6} 22 ( 1,   2/5,   1/10,   -1/5,   -1/2) prim. 2nd derived design of Leech lattice example
5 classes
5 32 { 5, 4, 3, 2, 1;   1, 2, 3, 4, 5 } 5 (1,   3/5,   1/5,   -1/5,   -3/5,   -1) Q-bip.
Q-antip.
Q-bip. double of Clebsch (d.r.g.)
5 54 { 6, 5, 9/2, 3/2, 1;   1, 3/2, 9/2, 5, 6 } 6 (1,   1/2,   1/4,   -1/4,   -1/2,   -1) Q-bip.
Q-antip.
Q-bip. double of Schläfli
5 200 { 22, 21, 16, 6, 1;   1, 6, 16, 21, 22 } 22 (1,   4/11,   1/11,   -1/11,   -4/11,   -1) Q-bip.
Q-antip.
Q-bip. double of Higman-Sims (d.r.g.)
5 224 { 21, 20, 49/3, 14/3, 1;   1, 14/3, 49/3, 20, 21 } 21 (1,   1/3,   1/9,   -1/9,   -1/3,   -1) Q-bip.
Q-antip.
Q-bip. double of McL1(x) (first subconstituent)
5 324 { 21, 20, 18, 3, 1;   1, 3, 18, 20, 21 } 21 (1,   2/7,   1/7,   -1/7,   -2/7,   -1) Q-bip.
Q-antip.
Q-bip. double of McL2(x) (second subconstituent)
5 486 { 22, 20, 27/2, 2, 1;   1, 2, 27/2, 20, 22 } 22 ( 1,   7/22,   2/11,   -1/11,   -5/22,   -1/2 ) Q-antip. dismantle dual scheme of coset graph of shortened extended ternary Golay code
5 550 {22, 21, 121/6, 11/6, 1;   1, 11/6, 121/6, 21, 22} 22 (1,   1/4,   1/6,   -1/6,   -1/4,   -1) Q-bip.
Q-antip.
Q-bip. double of McL
5 47104 { 23, 22, 529/25, 184/9, 483/25;   1, 46/25, 23/9, 92/25, 23/3} 23 (1,   7/15,   1/5,   -1/15,   -1/3,   -3/5) prim. Derived design of Leech lattice example
6 classes
6 1536 { 21, 20, 16, 8, 2, 1;   1, 2, 4, 16, 20, 21 } 21 ( 1,   3/7,   5/21,   1/21,   -1/7,   -1/3,   -11/21) Q-antip. dismantle dual code of triply truncated subcode of extended binary Golay code (see p365 in [BCN])
6 196560 { 24, 23, 288/13, 150/7, 104/5, 81/4;   1, 24/13, 18/7, 16/5, 15/4, 24} 24 ( 1,   1/2,   1/4,   0,   -1/4,   -1/2,   -1) Q-bip. shortest vectors in the Leech lattice
7 classes
7 1782 {22,21,121/6,55/4,33/4,11/6,1;   1, 11/6, 33/4, 55/4, 121/6, 21, 22} 22 (1,   1/2,   1/4,   1/8,   -1/8,   -1/4,   -1/2,   -1) Q-bip.
Q-antip.
Q-bipartite double of dual polar graph on 891 vertices
8 classes
9 classes
10 classes
11 classes
11 94208 { 23, 22, 529/25, 184/9, 483/25, 46/3, 23/3, 92/25, 23/9, 46/25, 1;   1, 46/25, 23/9, 92/25, 23/3, 46/3, 483/25, 184/9, 529/25, 22, 23 } 23 (1,   3/5,   7/15,   1/3,   1/5,   1/15,   -1/15,   -1/5,   -1/3,   -7/15,   -3/5,   -1) Q-bip.
Q-antip.
Q-bipartite double of scheme on 47,104 above