Question

In the context of context-free grammars, which of the following sequences can be generated by a CFG but not by a regular expression? All strings of equal length. All strings with an even number of 'a's. a^n b^n where n?0 and the symbol ^ signifies exponentiation All strings starting and ending with the same character.

          In the context of context-free grammars, which of the following sequences can be generated
by a CFG but not by a regular expression?
All strings of equal length.
All strings with an even number of 'a's.
a^n b^n where n?0 and the symbol ^ signifies exponentiation
All strings starting and ending with the same character.

In the context of context-free grammars, which of the following sequences can be generated
by a CFG but not by a regular expression?
All strings of equal length.
All strings with an even number of 'a's.
a^n b^n where n?0 and the symbol ^ signifies exponentiation
All strings starting and ending with the same character.

Added by Isaac P.

Computer Science and Information Technology

Trishna Knowledge Systems 2018 Edition

Instant Answer

Solved by Expert Shaik Dadasaheb

02/16/2022

Step 1

This is because a CFG can generate strings of any length by using recursion and rules to generate strings of equal length, while regular expressions have limitations in terms of counting and generating strings of equal length. Show more…

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In the context of context-free grammars, which of the following sequences can be generated by a CFG but not by a regular expression? All strings of equal length. All strings with an even number of 'a's. a^(^(^()))nb^(^(^()))n where n>=0 and the symbol ^(^(^())) signifies exponentiation All strings starting and ending with the same character. In the context of context-free grammars, which of the following sequences can be generated by a CFG but not by a regular expression? All strings of equal length. All strings with an even number of 'a's. a^n b^n where n>=0 and the symbol signifies exponentiation All strings starting and ending with the same character.