Definition 4.5 of rule has:
A rule is a pair R≔(B,H) such that B and H are graph patterns and Var(H)⊆B.
where it should have Var(H)⊆Var(B).
The paragraph after this says:
The restriction Var(H)⊆B ensures that the results of this substitution is a graph, with no variables in H left unsubstituted.
with the same mistake.
Definition 4.5 of rule has:
where it should have Var(H)⊆Var(B).
The paragraph after this says:
with the same mistake.