List the application of regular expression. 16 Write the formula for convert DFA to RE (Regular expression). If the accepting states are separated from the start state then the language is empty. If there is a path available the languages non-empty. The emptiness is defined by checking whether there is a path from the start sate to some accepting state. How do you test the emptiness of regular language? Then there exists a constant n such that for every in L such that |w|≥n. SNSCT – Department of Compute Science and EngineeringįORMAL LANGUAGE AND AUTOMATA THEORY Let L be a regular language.
Define pumping lemma for regular languages. Regular expressions obey many laws of arithmetic. Describe the algebra of regular expression. + Operator is having the lowest precedence. Next the concatenation or dot operator (.).
Operator is having the highest precedence. What is the order of precedence of operators used in regular expression? i.
Write the exp for the language starting with and has no consecutive b’s reg exp=(a+ab)*ġ2. r1Ur2= r1 +r2 r1.r2= r1r2 ( r )*=r* The class of regular sets are closed under complementation, substitution, homomorphism and inverse homomorphism.ġ1. What is the closure property of regular sets? The regular sets are closed under union, concatenation and Kleene closure. E.g.: The collection of the four letters. Kavitha Lecturer/CSE R.Durga Lecturer/CSEġ.
SNS COLLEGE OF T ECHNOLOGY ECHNOLOGY COIMBATORE – 35ĭEPARTMENT OF COMPUTER SIENCE AND ENGINEERING (UG & PG) Third Year Computer Science and Engineering, 5 th SemesterĢ Marks Question and Answer Subject Code & Name: Formal Language and Automata Theory Prepared by: M.