def is_fast(protocol, valuation, disabled):
graph, vertices, edges = transformation_graph(protocol, valuation,
disabled)
components, _, is_bottom = label_components(graph, attractors=True)
U = {q for q in vertices if not is_bottom[components[vertices[q]]]}
R = {q: set() for q in vertices}
expV = set()
for (p, q) in edges:
if components[vertices[p]] != components[vertices[q]]:
for t in edges[p, q]:
expV.add(t.pre)
if t.pre not in disabled:
for r in (set(t.pre) & U):
R[r].add(t.pre)
for q in U:
formula = Formula(valuation, disabled)
formula.assert_some_pair_present(expV)
formula.assert_some_states_present({q})
if not formula.implies_some_present_tautology_check(R[q]):
return False
return True
