• Input: G = (N, T, P, S); item I
• Output: Closure(I)
• Method:
• Closure(I) := {I};
• Apply the following rule until Closure(I) cannot be changed:
• if A ® y·Bz Î Closure(I) and B ® x Î P then
  add B ® ·x to Closure(I)
Closure of Item: Algorithm
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Note: Closure(I) is the set of items defined by the following algorithm: