CFG Problem Solve Tip


# Problem Solve Tip
- design CFG is like peeling onion - start from right and left side ← cannot effect both side → so represent required string - ex. a^(k+n)b^k c^n → a^n a^k b^k c^k → we can peel n
- CFG only solve add → so make  sub to add - ex. a = b - c → b = a + c
- remove lambda → unit → redundant → CNF
1. Remove λ-productions
2. Remove unit productions
3. Remove redundant symbols










