The beta side of the network: a graph of Rete.Network.Node descriptions.

Internal. The compiler walks each production's sorted left hand side in order. It adds one node per condition, under the nodes the previous condition produced. Node 0 is an artificial root, so the graph has a single entry point.

Parents are a list. A disjunction adds each branch as its own chain, and hands the union of the branch terminals to the next condition. So the branches re-converge on it. That is why the compiler never flattens the LHS to disjunctive normal form. DNF over the whole LHS costs work that is exponential in the number of disjunctions. To fan out for each condition costs only linear work.

Sharing requires equality and the same parent set. Equality alone is a correctness bug. In a({:customer, cid}, {:order, cid, amt}) and b({:vendor, cid}, {:order, cid, amt}), the two order conditions are equal, but they sit under different parents. Sharing them would let a :vendor token join a :customer's elements. A terminal keys on the production's identity instead, so two rules with an identical LHS fire independently.

{:or, []} is false, and the compiler builds nothing for a path through one. Otherwise, a keyless condition after a false element would become an entry point the alpha index feeds. An unsatisfiable rule would then fire on every fact. See docs/design/network.md §4.