00:01
We're asked to construct a touring machine that computes the function f of n1n2 is equal to n1 plus n2 plus 1 for all non -negative pairs of integers, n1 and 2.
00:26
Now notice that we're going to start in our touring machine with an expression of the form n1 plus 1 1s followed by a star.
00:38
Followed by n2 plus 1 ones.
00:43
This is a total of n1 plus n2 plus 2 ones, separated by an asterisk.
00:53
And notice that we want to end up with an expression which has n1 plus n2 plus 1 plus 1 or plus 2 ones, with no asterisk.
01:06
So really we want to keep the same number of ones as, as in the start, but we want to just get rid of this asterisk.
01:14
So one way to do this is to remove the first one from the string, and then we're going to add it back by replacing the asterisk with a one.
01:27
We will get the desired end.
01:31
So this means that starting in state s0, inevitably, because this is a non -negative integer, we're going to encounter a 1.
01:39
And when we do, we're going to shift into a new set...