00:01
The language l is not regular.
00:07
This can be shown using the pumping lemma for regular languages.
00:13
Suppose l is regular and let n be the pumping link given by the pumping lemma.
00:17
Consider the string w equals a to the n, b, the n, c to the 2n.
00:23
This string is an l and the absolute value of w equals 4n, which has got to be greater than an equal to n.
00:33
By the pumping element, w can be written as x, y, z, where the absolute value of xy is less than equal to n, the absolute value of y is greater than equal to one, and for all i greater than equal to zero, x, y to the i z is also an n, or excuse me, an l...