
Let REPEATTM = { | M is a TM, and for all s L(M), s = uv where
u = v }. Show that REPEATTM is undecidable. Do not use Rice’s
Theorem.
Let REPEATTM = { <M>M is a TM, and for all s E L(M), s = uv where u = v}. Show that REPEATM is undecidable. Do not use Rice's Theorem.
8. (15) Let REPEATTM = { <M>M is a TM, and for all s € L(M), s = uv where u = v}. Show that REPEATM is undecidable. Do not use Rice's Theorem.
Let REPEATTM = {<M> Mis a TM, and for all s E L(M), s = uv where u =v}. Show that REPEATTM is undecidable. Do not use Rice's Theorem.
2. Let L = {hMi: M is a Turing machine that accepts at least two
binary strings}. a) Define the notions of a recognisable language
and an undecidable language. [5 marks] b) Is L Turing-recognisable?
Justify your answer with an informal argument. [5 marks] c) Prove
that L is undecidable. (Hint: use Rice’s theorem.) [20 marks] d)
Bonus: Justify with a formal proof your answer to b). [20
marks]
2. Let L-M M): M is a Turing machine that accepts...
(10) Let L = { <M> | M is a TM that accepts sR whenever it accepts s } . Show that L is undecidable.
Let PALINDROMEDFA = { | M is a DFA, and for all s L(M), s is a
palindrome }. Show that PALINDROMEDFA P by providing an algorithm
for it that runs in polynomial time.
Let PALINDROMEDFA = {<M> Mis a DFA, and for alls e L(M), s is a palindrome }. Show that PALINDROMEDFA E P by providing an algorithm for it that runs in polynomial time.
7.(15) Let PALINDROMEDFA = { <M> Mis a DFA, and for all s E L(M), s is a palindrome } Show that PALINDROMEDFA E P by providing an algorithm for it that runs in polynomial time.
Help me answer this question plz!
4. Let L = { (A) M is a Turing machine that accepts more than one string } a) Define the notions of Turing-recognisable language and undecidable language. b) Is L Turing-recognisable? Justify your answer with an informal argument. c) Justify with a formal proof your answer to b) d) Prove that L is undecidable. (Hint: use Rice's theorem.) e) Modify your answer to b) when instead of L you have the language Ln...
19. (1 point) Suppose that L is undecidable and L is recognizable. Which of the following could be false? A. I is co-Turing recognizable. B. I is not recognizable. C. I is undecidable. D. L* is not recognizable. E. None of the above. 20. (2 points) Let ETM {(M)|L(M) = 0} and EQTM = {(M1, M2)|L(Mi) = L(M2)}. We want to show that EQTM is undecidable by reducing Etm to EQTM and we do this by assuming R is a...
Let PALINDROME DFA = { <M> | M is a DFA, and for all s E L(M), s is a palindrome }. Show that PALINDROME DFA E P by providing an algorithm for it that runs in polynomial time.