" M(n) = 0^inf < A 1^n 0^inf." I read that as an infinite string of 0's (0^inf), then the tape head (<), then a string of exactly n 1's (1^n), then infinitely

" M(n) = 0^inf < A 1^n 0^inf." I read that as an infinite string of 0's (0^inf), then the tape head (<), then a string of exactly n 1's (1^n), then infinitely many 0's. So a block of n 1's starting at the tape head, surrounded by endless 0's to the left and right.