theory of computing (ambiguity)

1. REMOVING AMBIGUITY
FROM CFG
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2. Group Members:
1. Muradul Islam Jamil (152-35-1203)
2. Mahadi Hasan Joy (152-35-1207)
3. Mazed Mourshed (152-35-1215)
Md. Anwar Hossen
Lecturer, Dept. of Software Engineering
Daffodil International University
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3. AMBIGUITY IN CFG
If a context free grammar has more than one derivation tree
for some string, it is called an ambiguous grammar. There
exist multiple right-most or left-most derivations for some
string generated from
that grammar.
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4. PROBLEM
Check whether the grammar G with production rules −
S → AB | aaB
A → a | Aa
B → b
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5. SOLUTION
Let’s find out the derivation tree for the string “aab". It has two leftmost deriv
i) S → aaB → aab
ii) S → AB →AaB → aaB → aab
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6. ANOTHER PROBLEM
Check whether the grammar G with
production rules −
S → S + S | S * S | a
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7. SOLUTION
Let’s find out the derivation tree for the string “a+a+a". It has two leftmost d
i) S → S + S → S + S + S → a + a + S → a + a + a
ii) S → S + S → S + S + S → S + a + a → a + a + a
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8. SOLUTION
Let’s find out the derivation tree for the string “a+a*a". It has two leftmost de
i) S → S + S → a + S → a + S * S → a + a * a
ii) S → S * S → S + S * S → a + a * S → a + a * a
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9. THANK
YOU
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