As above, this rule ensures that a well-typed AM dependency tree is generated by locally checking the types.
if all types τ 2 that can be derived for k are incompatible with τ 1 , we fall back to an item for k with τ 2 = ⊥ (which always exists), along with an IGNORE edge from i to k. The complexity of this algorithm is O(n , where d is the maximal arity of the nodes in t r .