It was recalled that dislocations in such crystals were defined to be the intersections of dislocations in a high-dimensional lattice with an irrational cut which configured the physical space. This definition conferred upon them a number of unusual geometrical properties which could be studied by means of suitable extensions of the Volterra concept, or by using a topological approach. The latter often offered a complementary point of view. Among the unusual properties were the production of stacking faults under shear at low temperatures, reshuffling on stacking faults, and non-commutivity. These properties were suggested to have some effect upon the interplay between dislocations during deformation.

M.Kléman: Czechoslovak Journal of Physics, 1995, 45[11], 935-46