- Trending Categories
Data Structure
Networking
RDBMS
Operating System
Java
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
What are the identity rules for regular expression?
The two regular expression’s P and Q are equivalent (denoted as P=Q) if and only if P represents the same set of strings as Q does.
For showing the equivalence of two regular expressions we need to show some identities of regular expression’s
Let P, Q and R be the regular expressions then the identity rules are as follows −
- εR=R ε=R
- ε*= ε ε is null string
- (Φ)*= ε Φ is empty string
- ΦR=R Φ= Φ
- Φ+R=R
- R+R=R
- RR*=R*R=R+
- (R*)*=R*
- Ε+RR*=R*
- (P+Q)R=PR+QR
- (P+Q)*=(P*Q*)*=(P*+Q*)*
- R*(ε+R)=( ε+R)R*=R*
- (R+ε)*=R*
- Ε+R*=R*
- (PQ)*P=P(QP)*
- R*R+R=R*R
- Related Articles
- What are the rules for the body of lambda expression in Java?
- What are the rules for a local variable in lambda expression in Java?
- What are the rules for formal parameters in a lambda expression in Java?
- What are the Rules of Regular Expressions in Compiler Design?
- What are some of the rules of creating a CSS expression?
- What are regular expression repetition cases in Python?
- What are the basic rules for JavaScript parameters?
- Construct the Regular expression for the given languages.
- What are the rules for naming classes in C#?
- What are the basic scoping rules for python variables?
- What are the golden rules for handling your money?
- What are the rules for calling the superclass constructor C++?
- What are repeating character classes used in Python regular expression?
- What are the basic rules for defining variables in C++?
- What are the scoping rules for lambda expressions in Java?

Advertisements