Product Construction - AND - ANS-both states need to be final
Product Construction - OR - ANS-any state with a final can be one
Product Construction - XOR - ANS-only one state can have a final
CFG for Palindrome with {0,1}* - ANS-Consider side cases: e,0,1, 0110 (even length),
01110(odd length)
Grammar:
S-> 0S0 | 1S1 | 0 | 1 | e
Regular Languages Closure Properties - ANS-- Union
- Concatenation
- Star
- Intersection
- Complementation
CFLs are closed under: - ANS-- Union
- Concatenation
- Star
Decidable Languages are closed under: - ANS-- Union
- Concatenation
- Star
- Intersection
- Complementation
Recognizable Languages are closed under: - ANS-- Union
- Concatenation
- Star
- Intersection
To show that a language L is NOT regular, one can - ANS-- show that L* is not regular
-use the pumping lemma for regular languages.
- use closure properties.
To show that a language is regular, one can - ANS-- give a DFA that recognizes the language.
- give an NFA that recognizes the language.
- give a regular expression that describes the language