00:02
We are given sets and we are asked to express each of these sets using a regular expression.
00:10
In part a, we're given the set containing all strings with 0, 1, or 2 bits.
00:33
In other words, less than are equal to 2 bits.
00:39
Well, recognize that all strings with 0, 1, or 2 bits are lambda 0 ,0, 0 ,000, 1, 0 ,000, 1.
00:57
One zero and one one one and we see this can be written in as a regular expression lambda union with zero union with one union with zero union with zero union with zero union with zero one union with one one in part b we are given the set of strings of two zeros followed by 0 or more 1s, and ending with a 0.
02:28
We have that all strings with 0 more 1s is 1 star, and the set of strings of 2 zeros, followed by 0 more 1s, and ending with a 0 is going to be a concatenation of strings and sets.
02:49
So we get in regular form 0 0 for the first 2 0s, then 1 star for the 0 more 1s, and finally a 0.
03:01
For the last ending zero.
03:07
In part c, we are given a set of strings with every one followed by two zeros.
04:16
Now this can be seen as consisting of the strings 1 -0 and 0, since it can only contain block one zero or single zeros.
04:50
And so it follows that this set can be written in regular form as 1 -0 -0 union with 0 star.
05:21
In part d, we're given the set of strings not containing or ending in 0 -0 and not containing 1 -1.
06:02
So we have the set of strings not containing 1 -1 consists of 0 or more zeros, or block...