Assume a shifted derivation x of state p is a direct descendant from derivation x of state p , then p ∈ R(p ), and we have: which is proved in Section 5.1.
more formally, we can conclude that where T (p) is the left corner states of shifted state p, defined as which represents the set of all states that have the same reducibility as a shifted state p. Algorithm 2 Lazy Expansion of Algorithm 1.