This$/$These problem$($s$)$ is$/$are undecidable $($as defined in the course$)$: EQ TM the problem of determining whether two given Turing machines are equivalent $($i$.$e$.,$ they accept the same language$).$ E TM the problem of determining whether a Turing machine accepts no input $($the empty language$)$ HALT TM $.$ the problem of determining whether a Turing machine halts $($by accepting or rejecting$)$ on a given input All of these are undecidable. REGULAR TM $.$ the problem of determining whether a given Turing machine has an equivalent finite automaton $($ meaning it accepts a regular language$).$