Terwilliger Algebras — T(x)

Distance-Regular Graphs with Valency Three
Barnabás Valkó  ·  University of Wisconsin–Madison
The following is a summary of the irreducible T-modules (ITMs) and corresponding dimensions of the Terwilliger algebra (dim T) for the 13 distance-regular graphs with valency three.
Select a graph to explore its Terwilliger algebra in detail.
Graph Γ |Γ| # ITMs # Types dim T Formulation
K₄ 4 3 2 22 + 12 = 5 Explore →
K₃,₃ 6 4 3 32 + 12 + 12 = 11 Explore →
Petersen 10 6 4 32 + 22 + 12 + 12 = 15 Explore →
3-cube 8 3 2 42 + 22 = 20 Explore →
Heawood 14 6 3 42 + 22 + 22 = 24 Explore →
Pappus 18 7 5 52 + 32 + 12 + 22 + 22 = 43 Explore →
Tutte's 8-cage 30 13 6 52 + 32 + 32 + 12 + 22 + 12 = 49 Explore →
Desargues 20 6 4 62 + 42 + 22 + 22 = 60 Explore →
Coxeter 28 8 6 52 + 52 + 22 + 42 + 12 + 22 = 75 Explore →
Dodecahedron 20 4 3 62 + 62 + 22 = 76 Explore →
Tutte's 12-cage 126 37 10 72 + 4(52) + 32 + 2(22) + 2(12) = 168 Explore →
Foster 90 18 9 92 + 2(72) + 52 + 3(42) + 22 + 12 = 257 Explore →
Biggs-Smith 102 10 5 82 + 132 + 112 + 92 + 42 = 451 Explore →