Provide a regular expression for the following languages:
(a) the set of all strings over {a, b} that start with ab and end with ba,
(b) the set of strings over {a, b} where four consecutive occurrences of both letters occur in every word.
a) ab(a+b)*ba b) ((a+b)*aaaa(a+b)*bbbb(a+b)*) + ((a+b)*bbbb(a+b)*aaaa(a+b)*)
Provide a regular expression for the following languages: (a) the set of all strings over {a,...
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!!!
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...
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....
Exercise 3.1.1: Write regular expressions for the following languages: * a) The set of strings over alphabet {a,b,c} containing at least one a and at least one b. b) The set of strings of O's and l’s whose tenth symbol from the right end is
Automata Theory - Finding a regular expression for each of the following languages over {a,b} or {0,1}: I've written the solution . Please show steps on how to approach the problems that I mentioned in parentheses. The ones where I put my own regular expression check and see if it's still right. Thanks Strings with .... odd # of a's ---> (b*ab*ab*)b*ab* even # of 1's ---> 0*(10*10*)* ---> my answer was 0*10*10* (is this still right?) start & end...
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...
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...
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...
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 start with 00 or end with 101 (or both). Syntax The union is expressed as R|R, star as R*, plus as R+, concatenation as RR. Epsilon is not supported but you can write R? for the regex (R|epsilon).
Construct regular expressions for the following languages over the alphabet {a, b}: a. Strings that do not begin with an “a”. b. Strings that contain both aa and bb as substrings.