Problem on empty string
Give an algorithm that, given a grammar G = (V, Σ, R, S), decides whether the grammar G can derive the empty string.
Expert
Suppose that ^ does not belongs to L(G).
We use the algorithms for removing useless symbols and productions. If S is found to be useless, then L(G) is empty; if not, then L(G) contains at least one element.
I have a problem in NFA-DFA. Can somone give the Proof of the theorem of NFA-DFA equivalence ?
Proof the theorem that the class of regular languages is closed under union; that is, if L1 is recognized by a NFA and L2 is recognized by a NFA, then L1 υ L2 is recognized by a NFA as well.
Describe the Strategy of TOC computation box in brief ?
Define various Terminologies used in TOC ?
Define the term Regular expressions ?
What do you mean by Formal description of NFA operation ?
Let REGEXP be the language of valid regular expressions over {a, b}. That is, REGEXP is the set of all strings over the symbols Σ= {a, b, (,), U,*, ^} that are valid regular expressions. For example, the string “a (a U b)" is in REGEXP, whereas the string
What do you understand by the term Finite Automata ?
Let s1 and s2 be two strings of lengths m and n respectively. By definition, a superstring of s1 and s2 is one which contains s1 and s2 as substrings. Give a dynamic programming algorithm to compute a shortest superstring of t
Let α be a regular expression of length n. (a) Using procedures shown in class, if we convert α into a regular expression β such that L(β) = L(α). How long β might be? Give a reasonably tight upper bound.
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