# hw1sol - CS 503 Foundations of Computer Science 01/18-03/06...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CS 503 Foundations of Computer Science 01/18-03/06 2012 at Cisco Solutions for Homework 1 1. Exercise 30 on page 60. Solution: The set of strings over { a,b } that do not begin with the substring aaa is represented by ( λ ∪ a ∪ aa )( λ ∪ b + ( a ∪ b ) * ) (15 points) 2. Exercise 34 on page 61. Solution: The set of even length strings over { a,b } is represented by (( a ∪ b )( a ∪ b )) * and the set of odd length strings is represented by ( a ∪ b )(( a ∪ b )( a ∪ b )) * Therefore the set of odd length strings over { a,b } which contain bb is represented by (( a ∪ b )( a ∪ b )) * bb ( a ∪ b )(( a ∪ b )( a ∪ b )) * [ ( a ∪ b )(( a ∪ b )( a ∪ b )) * bb (( a ∪ b )( a ∪ b )) * (15 points) 3. Exercise 39.d on page 61. Solution: ( a ∪ b ) * = ( a ∪ ba * ) * = ( a * ∪ ba * ) * Here in the first equality we have used the third regular expression identity in 12. of Table 2.1, and in the second equality we have used the first identity in 12. (15 points) 1 4. Let Σ be an alphabet, and4....
View Full Document

{[ snackBarMessage ]}

### Page1 / 6

hw1sol - CS 503 Foundations of Computer Science 01/18-03/06...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online