Pick all condition(s) for TMs to "accept a string".

Question

BlackTom AI · Accepted Answer

A Turing machine (TM) accepts an input precisely when it reaches an accepting (final) state and stops. In formal terms, an input string x is accepted by a TM if there exists a computation path that, starting from the initial configuration with x on the tape, leads to a configuration whose state is an accepting state and from which the machine halts.

Relevant knowledge points and concepts:
1. TM components: finite control (states), tape, head. Acceptance is about the control entering a designated accepting state and halting.
2. Halting vs. non-halting: acceptance requires halting in an accepting state; merely visiting an accepting state but continuing would be nonstandard unless the TM is defined to halt upon entering that state.
3. Variants: nondeterministic TMs accept if some branch halts in an accepting state. Recognition vs. decision: recognizers may loop on nonmembers; deciders halt on all inputs.

Step-by-step reasoning:
1. Option "It halts in an accepting state": matches the standard definition — the machine reaches an accepting state and halts; therefore the input is accepted.
2. Option "The stack is not empty.": TMs do not use a stack as their primary acceptance condition; this property is relevant to pushdown automata, not general TMs. A nonempty tape or stack does not determine acceptance.
3. Option "The tape contains non-blank symbol.": The presence of non-blank symbols on the tape is neither necessary nor sufficient for acceptance. A TM could accept with a blank tape or leave non-blank symbols without implying acceptance; acceptance depends on state and halting, not tape content alone.
4. Option "None is correct.": Since the first option is correct, "None is correct" is false.

Why the correct answer is correct: Standard definitions of TM acceptance require the machine to halt in an accepting state (for deterministic and for a successful branch in nondeterministic machines). Other choices describe irrelevant or insufficient conditions.

Conclusion: The correct choice is "It halts in an accepting state," which matches the provided answer.

Pick all condition(s) for TMs to "accept a string".多项选择题

类似问题

Pick all true statements about "TMs simulation" abilities:

Which language does a Turing machine accept or recognize?

Nondeterministic TMs are a collection of standard TMs.

What is the "associated language" of the following TM over Sigma = { a , b }?

Which language does a Turing machine accept or recognize?

Which of the following is NOT a characteristic of a Turing machine?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单