given ∑ = {a,b}:
1. describe in English the languages denoted by the regular expression: (a+b)*b(a+b)*
2. Write a regular expression: L(w) = {w | w has exactly a single substring abaa or exactly a single substring babb}
3. Write a regular expression for the following language: L(w) = {w | w ends in bb and does contain the substring aba}
a) L(w) = {w | w has atleast one b}
b) b*aa*baaa*b*+a*bb*abbb*a*
c)(a+b)*aba(a+b)*bb
given ∑ = {a,b}: 1. describe in English the languages denoted by the regular expression: (a+b)*b(a+b)*...
3) Construct a regular expression defining each of the following languages over the alphabet {a, b}. (a) L = {aab, ba, bb, baab}; (b) The language of all strings containing exactly two b's. (c) The language of all strings containing at least one a and at least one b. (d) The language of all strings that do not end with ba. (e) The language of all strings that do not containing the substring bb. (f) The language of all strings...
L = {w|w contains the substring bab} give the regular expression that describes L are the 2 languages L and L* the same language? Is L(aba)* a regular language?
Construct a regular expression that defines the language L (say) containing all the words with either exactly one aba-substring or exactly one bab-substring but not both aba- and bab-substrings. (Hint: For example, the word abab does not belong to L.)
1. Design an NFA (Not DFA) of the following languages. a) Lw E a, b) lw contain substring abbaab) b) L- [w E 10,1,2) lsum of digits in w are divisible by three) c) L-(w E {0,1,2)' |The number is divisible by three} d) The language of all strings in which every a (if there are any) is followed immediately by bb. e) The language of all strings containing both aba and bab as substrings. f L w E 0,1every...
Construct DFA's that recognize the following languages over the alphabet {a,b}: 1. {w|w is any string except abba or aba}. Prove that your DFA recognizes exactly the specified language. 2. {w|w contains a substring either ababb or bbb}. Write the formal description for this DFA too.
Give the regular expressions of the following languages (alphabet is ab): a. {w | w has a length of at least three and its second symbol is a b} b. {w | w begins with an a and ends with a b} c. {w | w contains a single b} d. {w | w contains at least three a's} e. {w | w contains the substring baba} d. {w | w is a string of even length} e. The empty...
Regular expressions, DFA, NFA, grammars, languages Regular Languages 4 4 1. Write English descriptions for the languages generated by the following regular expressions: (a) (01... 9|A|B|C|D|E|F)+(2X) (b) (ab)*(a|ble) 2. Write regular expressions for each of the following. (a) All strings of lowercase letters that begin and end in a. (b) All strings of digits that contain no leading zeros. (c) All strings of digits that represent even numbers. (d) Strings over the alphabet {a,b,c} with an even number of a's....
1. Write regular expressions to capture the following regular languages: (a) The set of binary strings which have a 1 in every even position. (Note: odd positions may be either 0 or 1.) (b) The set of binary strings that do not contain 011 as a substring. (c) Comments in Pascal. These are delimited by (* and *) or by { and }, and can contain anything in between; they are NOT allowed to nest, however. 2. Write a DFA...
1. L is the set of strings over {a, b) that begin with a and do not contain the substring bb. a. Show L is regular by giving a regular expression that denotes the language. b. Show L is regular by giving a DETERMINISTIC finite automaton that recognizes the language.
Question 3. Write down a regular expression that denotes the following language. L = {a mb n : m + n is even} Question 4. Let L1 be the language denoted by ab∗ a ∗ and let L2 be the language denoted by a ∗ b ∗ a Write a regular expression that denotes the language L1 ∩ L2.