What are the regular expressions for sets of strings composed of zeros and ones which: 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
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.
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....
Write a regular expression that captures the set of strings composed of 'a', 'b', and 'c', where any string uses at most two of the three letters (for example, "abbab" is a valid string, or "bccbb", or "ccacaa", but not "abccba": strings that contain only one of the three letters are also fine). Give a non-deterministic finite automaton that captures the regular expression from Using the construction described in class, give a deterministic version of the automaton. Repeat the previous...
Provide regular expressions for the following languages: a.) The set of strings over {0,1} whose tenth symbol from the right end is 1. b) The set of strings over {0,1} not containing 101 as a sub-string. ***IMPORTANT: PLEASE SHOW ALL WORK AND ALL STEPS, NOT JUST THE ANSWERS!!!
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...
Preliminaries For this lab you will be working with regular expressions in Python. Various functions for working with regular expressions are available in the re module. Fortunately, Python makes it pretty easy to check if a string matches a particular pattern. At the top of the file we must import the re module: import re Then we can use the search() function to test whether a string matches a pattern. In the example below, the regular expression has been saved...
John Doe claims that the language L, of all strings over the alphabet Σ = { a, b } that contain an even number of occurrences of the letter ‘a’, is not a regular language. He offers the following “pumping lemma proof”. Explain what is wrong with the “proof” given below. “Pumping Lemma Proof” We assume that L is regular. Then, according to the pumping lemma, every long string in L (of length m or more) must be “pumpable”. We...
For each of the languages listed below, give a regular expression that generates the lan- guage. Briefly justify your answer. (a) The set of strings over (a, b such that any a in the string is followed by an odd number of b's. Examples: bbbab E L, but abb f L. (b) The set of strings over fa, b in which there is an a in every even position and the total number of b's is odd, where the first...
Give regular expressions generating the languages of 1. {w over the alphabet of {0, 1} | w is any string except 11 and 111} 2. {w over the alphabet of {0, 1} | w contains at least two 0’s and at most one 1} 3. {w over the alphabet of {0, 1} | the length of w is at most 9} 4. {w over the alphabet of {0, 1} | w contains at least three 1 s} 5. {w over...