  This paper explores a particular statistical model on 6-valent graphs with
special properties which turns out to be invariant with respect to certain
Roseman moves if the graph is the singular point graph of a diagram of a
2-knot. The approach uses the technic of the tetrahedral complex cohomology. We
emphasize that this model considered on regular 3d-lattices appears to be
integrable. We also set out some ideas about the possible connection of this
construction with the area of topological quantum field theories in dimension
4.
