for s2,Tape alphabet Г can never be same as input alphabet ∑ . The tape
alphabet always contains the blank symbol, but the input alphabet cannot
contain this symbol.s2 is true
for S3 ,A Turing machine’s head can be in same location in two successive
steps, but it is possible only when the Turing machine’s head is on the
first tape square and it tries to move left. It will stay in place instead of
falling off the tape. However, if it is not on the leftmost square, then in
the next move the tape head cannot remain in the same location. So,
Turing machine’s head can be in same location in two successive
steps .s3 is true