diff -r 3c504ca0ce95 -r 0941e450e8c2 Paper/Paper.thy --- a/Paper/Paper.thy Thu Feb 07 03:37:02 2013 +0000 +++ b/Paper/Paper.thy Thu Feb 07 03:40:23 2013 +0000 @@ -1369,7 +1369,7 @@ Analysing the universal Turing machine constructed in \cite{Boolos87} more carefully we can strengthen this result slightly by observing that @{text m} is at most - 2 in the output tape. This observation allows one to construct a UTM that works + 2 in the output tape. This observation allows one to construct a universal Turing machine that works entirely on the left-tape by composing it with a machine that drags the tape two cells to the right. A corollary is that one-sided Turing machines (where the tape only extends to the right) are computationally as powerful as our two-sided