| ¬ (S0 ≠ ∅ ∧ ¬ done0), ∀ n. ¬ reach(source, dest, n), done0 → dest ∈ S0, INV(S0, S, S1, n0, source), ((done0 ⊃ some(n0); fail)) ≠ fail ⊦ |
dest ∈ S0, INV(S0, S, S1, n0, source), ∀ n. ¬ reach(source, dest, n) ⊦ S0 = ∅, # S0 = 0
[[CONCRETESIMPRULES : ([CSIMPFORWARD : ⊦ s ≠ ∅ → # s ≠ 0], [CSIMPFORWARD : ⊦ a ∈ s → s ≠ ∅], [CSIMPSEQ : ⊦ some(m) ≠ fail])]]