Definition.                                         Link of an atom.

Let X be an atom. The external links of X are internal facts within X pointing to other atoms.

In the atomistic model the links are embedded into the atoms.This is a remarkable difference to traditional models.

Bi-directional links have their opposite side edges as complementary links. Static links are atom invocations in the corresponding command as well as structural links implemented by has-a and is-a relationships. Dynamic links are side effects, which are new atoms from simulation attached to the host atom by has-a and is-a links.