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How to tell if a machine is Turing machine equivalent

I found a Wikipedia article of a list of Turing machine equivalents. However, it doesn't tell a method of how to determine whether a given machine is Turing machine equivalent.

Do I need to use the definition of a Turing machine to prove it? Could you give an example?

Thanks.

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Ryan Li Avatar asked Jan 10 '11 09:01

Ryan Li


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2 Answers

The standard way of proving something turing complete is to implement one of the TM-equivalents in your machine. If that is possible to do, then your machine is turing-complete. If it's not, then it's not. So if I was trying to prove, say, that a new programming language is turing complete, I'd pick the TM-equivalent that's simplest to implement, and then show that my programming language can simulate it.

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keiter Avatar answered Oct 16 '22 08:10

keiter


Actually it cannot be really proven. At least, fully formalizing these common equality proofs might require much more formal logic than to be expected even in theoretical computer science. ( if you disagree, tell me! I am eager to discuss about this. )

However, it is mostly clear from context. You try build a simulation of a "machine" of scheme of computation A within another such model of computation B. This means B can simulate A, and hence has the full power of A. If you do vice versa, these two models are called equivalent.

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shuhalo Avatar answered Oct 16 '22 08:10

shuhalo