Show that the set of even length strings over {a,b} in which two middle symbols are same is not regular.

Show that the set of even length strings over {a,b} in which two middle symbols are...
Write down the regular expressions for the following set of strings over {a, b}: 1.Strings that contain no more than one occurrence of the string aa. 2.All strings containing aba: 3.All strings of odd length 4.A string in this language must have at least two a's. 5.All strings that begin with a, and have an even number of b Bonus - All strings with “a” at every odd position
Submit a DFA whose language is the set of strings over {a, b} of odd length in which every symbol is the same.
Let L be the language of binary strings of odd length such that the middle bit is 0. Show that L is not regular, and show that L is context-free.
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 1 - Regular Expressions Find regular expressions that define the following languages: 1. All even-length strings over the alphabet {a,b}. 2. All strings over the alphabet {a,b} with odd numbers of a's. 3. All strings over the alphabet {a,b} with even numbers of b’s. 4. All strings over the alphabet {a,b} that start and end with different symbols. 5. All strings over the alphabet {a, b} that do not contain the substring aab and end with bb.
Give a regular expression for the language of strings over {a,b} in which each substring of length 2 contains two distinct characters
Construct a regular expression that recognizes the following language of strings over the alphabet {0 1}: The language consisting of the set of all bit strings that contain two or three symbols.
Provide a regular expression for the set of strings over {a, b, c} such that the number of a’s equals the number of b’s and is less than or equal to 2.
For each problem below (except #8), show a regular expression representing the described set. The set of strings over {c, l, e, a, n} with length less than 5. The set of strings over {c, l, e, a, n} with length greater than 7 If you take the union of the regular expressions from the previous two problems, how many strings more does the corresponding set need to contain all of Σ* , where Σ = {c, l, e, a,...
1. Give a regular expression for the set of strings over {a, b, c} such that the sum of the number of a’s and the number of b’s is equal to 3.