Posted by **James** on Saturday, November 3, 2012 at 11:32am.

Question #1.

1. Say that L is regular over 0, 1. Is the set, {x|x = 0y,y ∈L } also regular?

2. For two regular languages

(a) Is M*L=L*M for any alphabet?

(b) Is it true if the alphabet is only {0,1}?

(c) Is it true if the alphabet is only {0}?

3. If L is regular, is the language of all prefixes of L regular? How about all the suffixes of L?

Example: If L={abc,d} then the prefix language of L is {abc,ab,a,e,d}. The suffix language of L is {e,c,cb,cba,d}.