Re: [PO] halting problem reading comprehension

From: David C. Ullrich (ullrich_at_math.okstate.edu)
Date: 09/05/04 

Date: Sun, 05 Sep 2004 05:38:51 -0500

On Sat, 04 Sep 2004 14:21:07 GMT, "Peter Olcott"
<olcott@worldnet.att.net> wrote:

>
>"David C. Ullrich" <ullrich@math.okstate.edu> wrote in message news:o8ejj05rpmk178m71ufsaqasmcjo7sfek7@4ax.com...
>> On Sat, 04 Sep 2004 08:14:26 GMT, "Peter Olcott"
>> <olcott@worldnet.att.net> wrote:
>
>> >I thought that hardware could overcome what software
>> >could not. Once you flip off the power switch all the
>> >software that is on the machine becomes utterly helpless.
>> >If you could physically create write only memory, then
>> >no machine could read this memory. If no machine
>> >could read this memory, then no machine could obtain
>> >the result of the Halt Analysis.
>>
>> you don't need to be able to reason your way out of a
>> paper bag to see why this doesn't matter, you just need
>> to read what people have explained many times: yes, if
>> you turn off the power then the routine that's used in
>> the proof can't run. that does not allow your ha to
>> perform an impossible calculation.
>
>If I write it to write only memory that should make it that another
>TM can't read it. I didn't figure in all the possible lying and cheating.
>When people pointed out all the lying and cheating, they forgot to
>mention that this could be used as input to a Halt Analyzer,

you really insist on continuing to demonstrate stupidity even after
you've admitted you were wrong about all this.

the things you say were never pointed out til recently were all
pointed out very clearly, many times. in particular i said the
following many times:

1. say t is one of your strange oha's.
2 let t' be a machine that does the same things as t,
  except that it returns 0 or 1 instead of doing whatever
  silliness you think makes a difference.
3. we have a proof that t' cannot exist.
4. hence t cannot exist.

the 'this could be used as input to a Halt Analyzer' is
part of the well-known and often repeated proof of step 3.

>rather
>than merely a way to break my Halt Analyzer.
>
>It was like this: I can use write only memory. Well that memory
>can be replaced with read write memory. That does not refute
>the case where the memory is not replaced.
>
>This would have broken this chain:
>I won't replace the memory on your machine, I will replace the
>memory on a copy of your machine.

in the context of the paticular bit of silliness you're
talking about here that's exactly what step 2 says.

>Then I will use this copy
>of your machine to form one input that your machine can not
>process.
>
>This was the key missing piece in every refutation. They never
>bothered to say that it would be used as input to my unmodified
>Halt Analyzer.

if you think that using t' as input to t is an essential part
of the proof then you're still very confused. the four steps
above show that the things you've suggested can't work, without
ever using t' as input to t.

>If they would have said this then the whole issue
>of not meeting the burden of proof of proving a negative would
>have never arisen.
>>
>>
>>
>> ************************
>>
>> David C. Ullrich
>>
>> sorry about the inelegant formatting - typing
>> one-handed for a few weeks...
>

************************

David C. Ullrich

sorry about the inelegant formatting - typing
one-handed for a few weeks...

Relevant Pages

  • Re: [PO] halting problem reading comprehension
    ... >mention that this could be used as input to a Halt Analyzer, ... I can use write only memory. ... >> David C. Ullrich ...
    (comp.theory)
  • Re: [PO] halting problem reading comprehension
    ... | than merely a way to break my Halt Analyzer. ... I can use write only memory. ... be able to detect every other program which is also a halt detector. ... Hence your version of the halting program will have to give up if it is ...
    (comp.theory)
  • Re: [PO] halting problem reading comprehension
    ... | than merely a way to break my Halt Analyzer. ... I can use write only memory. ... be able to detect every other program which is also a halt detector. ... Hence your version of the halting program will have to give up if it is ...
    (sci.logic)
  • Re: [PO] halting problem reading comprehension
    ... >>mention that this could be used as input to a Halt Analyzer, ... > silliness you think makes a difference. ... t' is to be used as input to my unmodified halt analyzer. ... >>can be replaced with read write memory. ...
    (comp.theory)
  • Re: What is the Result from Invoking this Halt Function?
    ... >The halt analyzer is not required to answer every question that is ever ... >asked no matter who is doing the asking. ... >> David C. Ullrich ...
    (comp.theory)