- #1

Heidi

- 411

- 40

Rovelli defines spin networks in this paper

https://arxiv.org/abs/1004.1780

for a trivalent node Vn = 0 (the volume)

nodes begin to "get" volume with the four valent case.

take a cube or a tetrahedron, each vertex is linkes to 3 nodes so they would have a null volume.

things are different if we take the reciprocal network: from a node inside a tetrahedron four edges can intersect the four faces.

then we are in the four valent case.

have we to be more precise to talk about the valence of a node?