3 ms·
IIRC, some language model proved that one-layer of loops can be proven to halt vs not-halt. As soon as you add a 2nd layer of loops however, you reach Turing-c
by dragontamer 3y ago
IIRC, some language model proved that one-layer of loops can be proven to halt vs not-halt.
As soon as you add a 2nd layer of loops however, you reach Turing-completeness and suddenly the halting problem becomes unsolvable.
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So you don't need to deny jmp/loops. You just need to deny _nested_ loops. And... find that old paper I read like 15 years ago to figure out the details to discriminate halt/not-halt in the single-layer loop language.
- napsterbr 3y agoYou could ask ChatGPT to find the paper for you! It told me the name of an old videogame I was trying to remember for years.
- jakear 3y agoThis is most assuredly false: while (state !== STOP): read = TAPE[index] [state, write, dir] = TABLE[read, state] TAPE[index] = write index = index + dir
- deleted 3y ago[deleted]
- vidarh 3y agoIt takes much more. You need to e.g. limit APIs you can call to ones that are also guaranteed to halt, and guarantee an exit condition that is guaranteed to occur, which means either seriously limiting input or adding additional implicit conditions. E.g. this Ruby program is undecidable: gets This one using a hypothetical gets guaranteed to eventually halt is still undecidable: while getsWithTimeout != "halt" end
- deleted 3y ago[deleted]