Lecture 20: Properties of Regular languages

Proof by regular expression and Finite Automata for regular languages are closed under union, Concatenation, Kleene closure and Complement operation. Examples of Complement for the following problems: 1. Design of DFA that will accept all string over {a, b} that is not having substring aa. 2. Design of DFA that will accept all string over {a, b} that perform complement of the language (start with a and end with b).