Question & Answer: Which of the following modifications / restrictions to finite automata would change the class of languages ac…..

Which of the following modifications / restrictions to finite automata would change the class of languages accepted relative to “normal” finite automata?

a) The ability to move the read head backwards (as well as forwards) on the input.

b) The ability to write on (as well as read from) the input tape.

c) Both a) and b) simultaneously.

d) Having 2 read-heads moving (independently, left-to-right) over the input.

e) Having one billion or less different states.