Friday, February 13, 2026

A knotted kagome "nanotube"

Among the smallest knotted (unicursal or single-cycle) kagome baskets are some elongated small-diameter shapes reminiscent of carbon nanotubes. Shown above is the medial graph of Plantri 15-253174, which has the following road code: 10.17 4.21 24.1 27.6 31.12 14.33 8.37 2.41 42.23 43.0 25.44 46.39 48.19 29.50 52.35 54.15 32.55 13.56 57.34 53.58 59.16 11.60 30.61 51.62 63.36 9.64 65.18 49.66 28.67 7.68 69.38 47.70 71.20 5.72 26.73 45.74 75.40 3.76 77.22

This shape can be lengthened 6 vertices at a time. Its shorter predecessor is Plantri 9-12 of the previous post. The endcaps in both baskets are the same, the middle section, which in the 3-regular Tait graph is all hexagonal faces, gets longer 6 hexagons at a time. In carbon chemistry this would be a non-classical fullerene since each end cap has 1 triangular, 1 square, and 1 pentagon face. The face histogram for the 3-regular graph is [0 0 0 2 2 2 9].

Wednesday, February 11, 2026

Unicursal deltahedra with some symmetry and vertex degrees less than 7


The graph dual of Plantri 9-12, and its realization as knotology weaving

A deltahedron is a polyhedron where all faces are equilateral triangles. A deltahedron is unicursal if its skeletal graph is a Tait graph of a knot. The "knot" in such case is a kagome basket, the weaving of which is easily encoded because of the simple structure of a knot as opposed to a multicomponent link.

A 3-connected triangulation of the sphere might describe a deltahedron if the geometry works for equilateral faces. The Plantri software which is built in to SageMath, can generate 3-connected triangulations. These can be filtered for unicursality by counting spanning trees (another feature built in to Sage Math): a plane graph is unicursal if it has an odd number of spanning trees. In the list of candidate unicursal deltahedra given here, the results have been further filtered to have no vertex of degree 7 or higher, and to have some symmetry, |Aut|>1, as these are perhaps the most interesting to weave.

The "road codes" given will be explained in a later post. The "Plantri identifiers" given here are the number of vertices in the triangulation followed by the listing ordinal when Plantri is asked to generate all 3-connected triangulations on the sphere with that number of vertices.

Unicursal polyhedral triangulations with |Aut|>1 and vertex degrees < 7

Plantri 5-0: |Aut|= 12 Vdeg = [2 3]
7.2 0.9 5.10 12.3 13.8 1.14 6.15 11.16 17.4

Plantri 7-1: |Aut|= 4 Vdeg = [2 3 0 2]
0.9 11.6 3.14 16.1 8.17 19.10 20.5 13.22 2.23 24.15 25.4 21.26 12.27 7.28 29.18

Plantri 7-2: |Aut|= 6 Vdeg = [3 0 3 1]
0.11 12.5 7.14 16.9 3.18 20.1 10.21 22.15 23.8 17.24 2.25 26.19 27.4 13.28 6.29

Plantri 7-3: |Aut|= 20 Vdeg = [0 5 2]
7.0 3.10 13.6 9.16 2.17 19.12 20.5 15.22 8.23 1.24 25.18 26.11 27.4 21.28 14.29

Plantri 8-8: |Aut|= 2 Vdeg = [1 3 3 1]
11.2 4.13 16.9 17.0 6.19 15.22 23.10 24.1 25.18 7.26 21.28 14.29 30.3 31.12 5.32 33.20 34.27 35.8

Plantri 9-12: |Aut|= 2 Vdeg = [2 2 2 3]
4.11 14.1 17.6 8.19 2.23 24.13 25.0 15.26 28.21 30.9 18.31 7.32 33.20 29.34 35.10 5.36 16.37 27.38 39.22 3.40 41.12

Plantri 9-27: |Aut|= 2 Vdeg = [1 4 1 3]
1.8 11.4 2.17 9.18 21.6 24.15 13.26 23.28 29.16 3.30 10.31 19.32 33.0 34.7 35.22 36.27 37.14 25.38 12.39 5.40 20.41

Plantri 9-31: |Aut|= 4 Vdeg = [2 3 0 4]
12.3 5.14 17.8 11.20 21.4 22.13 2.23 25.0 6.27 15.28 30.9 31.18 24.33 34.1 35.26 7.36 16.37 29.38 39.10 40.19 41.32

Plantri 9-32: |Aut|= 2 Vdeg = [2 1 4 2]
4.11 13.2 16.9 7.18 1.22 12.23 24.3 25.14 20.27 30.5 10.31 32.15 33.26 21.34 0.35 29.36 37.6 38.17 8.39 19.40 41.28

Plantri 9-40: |Aut|= 4 Vdeg = [0 5 2 2]
11.2 6.15 18.3 19.12 0.21 9.22 16.25 26.5 28.13 29.20 1.30 10.31 23.32 34.7 14.35 36.27 4.37 38.17 24.39 33.40 41.8

Plantri 9-47: |Aut|= 2 Vdeg = [1 2 5 1]
9.2 7.14 17.4 19.12 21.0 11.24 18.25 5.26 28.15 29.8 30.1 31.22 20.33 13.34 6.35 27.36 37.16 38.3 39.10 40.23 41.32

Plantri 10-140: |Aut|= 2 Vdeg = [1 4 1 4]
0.9 11.2 5.14 21.4 22.13 7.24 17.26 29.20 30.3 31.12 23.32 6.33 15.34 36.27 37.18 39.10 40.1 8.41 25.42 16.43 35.44 45.28 46.19 47.38

Plantri 10-141: |Aut|= 6 Vdeg = [0 3 6 1]
11.2 7.16 19.10 20.1 13.22 5.24 27.18 28.9 14.31 23.32 4.33 35.26 36.17 37.8 29.38 39.0 21.40 12.41 3.42 43.34 44.25 45.6 46.15 30.47

Plantri 10-176: |Aut|= 2 Vdeg = [1 3 3 3]
8.1 6.15 17.4 21.12 23.0 9.24 18.27 5.28 29.16 30.3 32.25 33.10 22.35 13.36 38.19 26.39 40.31 2.41 42.7 14.43 37.44 45.20 46.11 47.34

Plantri 11-382: |Aut|= 2 Vdeg = [2 2 2 5]
13.0 7.20 22.5 24.17 11.26 28.1 29.14 12.31 27.32 33.2 35.16 25.36 10.37 39.4 23.40 41.18 8.43 21.44 45.6 46.19 47.42 9.48 49.38 50.3 51.34 52.15 53.30

Plantri 11-719: |Aut|= 2 Vdeg = [2 2 2 5]
12.1 7.16 21.6 22.15 9.24 27.4 30.13 0.31 11.32 33.2 28.35 5.36 20.37 39.18 41.26 42.3 43.34 29.44 45.14 23.46 8.47 17.48 38.49 50.19 51.40 52.25 53.10

Plantri 11-724: |Aut|= 2 Vdeg = [0 4 4 3]
3.14 17.6 12.21 0.23 24.9 27.20 13.28 2.29 32.7 33.18 4.35 15.36 31.38 39.8 25.40 11.42 43.22 1.44 45.30 46.37 47.16 48.5 34.49 19.50 26.51 41.52 10.53

Plantri 11-739: |Aut|= 2 Vdeg = [0 5 2 4]
1.10 17.0 18.9 6.21 14.23 26.11 27.2 5.30 31.22 15.32 25.34 35.12 37.4 38.29 40.19 8.41 16.43 33.44 24.45 46.13 47.36 48.3 49.28 39.50 51.20 7.52 53.42

Plantri 11-976: |Aut|= 2 Vdeg = [1 4 1 5]
15.2 8.17 20.5 7.22 23.18 27.14 28.1 11.30 24.33 19.34 35.6 36.21 4.37 39.26 40.13 41.0 29.42 10.43 45.32 25.46 38.47 48.3 49.16 9.50 51.44 52.31 53.12

Plantri 11-980: |Aut|= 4 Vdeg = [2 3 0 6]
9.0 6.15 17.4 2.23 25.8 11.28 30.21 19.32 34.13 27.36 10.37 1.38 39.24 40.7 14.41 42.33 43.20 31.44 18.45 5.46 47.16 48.3 22.49 50.29 51.12 35.52 26.53

Plantri 11-1135: |Aut|= 4 Vdeg = [0 5 2 4]
3.10 17.2 18.9 6.21 13.24 27.16 28.1 22.31 32.5 34.19 8.35 37.30 23.38 12.39 41.26 42.15 43.0 29.44 36.45 46.7 20.47 48.33 4.49 11.50 51.40 52.25 53.14

Plantri 11-1155: |Aut|= 2 Vdeg = [3 0 3 5]
11.0 6.13 19.4 2.21 26.7 12.27 1.28 29.22 16.31 33.18 34.3 20.35 5.36 37.14 24.39 41.10 8.43 44.25 38.45 15.46 47.32 48.17 30.49 23.50 51.40 52.9 42.53

Plantri 11-1210: |Aut|= 2 Vdeg = [0 3 6 2]
1.10 15.6 3.20 13.22 25.0 26.9 28.17 4.31 21.32 12.33 35.24 37.8 27.38 39.18 41.30 5.42 14.43 23.44 34.45 46.11 47.2 48.19 49.40 50.29 16.51 7.52 36.53

Plantri 11-1232: |Aut|= 2 Vdeg = [2 1 4 4]
14.3 5.16 18.11 23.2 15.24 4.25 26.13 29.20 31.0 6.33 17.34 35.12 27.36 38.21 39.30 8.41 43.10 19.44 28.45 37.46 47.22 48.1 49.32 7.50 51.42 52.9 40.53

Plantri 12-7571: |Aut|= 2 Vdeg = [1 4 1 6]
15.6 1.20 11.22 24.9 27.18 4.31 12.33 23.34 35.10 36.21 37.2 39.30 5.40 14.41 43.8 25.44 45.0 46.19 47.28 16.49 7.50 42.51 52.13 32.53 54.3 55.38 56.29 57.48 17.58 26.59

Plantri 12-7572: |Aut|= 2 Vdeg = [1 4 1 6]
11.2 5.14 17.8 19.0 7.24 16.25 30.9 31.18 21.34 13.36 4.37 39.28 26.41 42.15 43.6 44.23 33.46 20.47 1.48 10.49 50.29 51.40 27.52 38.53 54.3 55.12 56.35 57.22 45.58 32.59

Plantri 12-7593: |Aut|= 2 Vdeg = [0 3 6 3]
11.0 5.16 20.1 21.12 6.25 17.26 28.3 30.13 31.22 9.34 18.37 27.38 39.4 40.15 42.23 43.32 10.45 35.46 48.7 24.49 50.41 14.51 52.29 2.53 54.19 36.55 47.56 57.8 58.33 59.44