Re: Incorrect requirements --- Computing the mapping from the input to HHH(DD)

On 12/05/2025 18:03, Ben Bacarisse wrote:

Richard Heathfield <rjh@cpax.org.uk> writes:
 

On 12/05/2025 01:38, Mike Terry wrote:

On 11/05/2025 18:11, Richard Heathfield wrote:

...

we have an undecidable computation,

No no, that doesn't make sense.

>
Agreed. Therefore, even *after* taking out all the dodgy code, the decider
must be broken.
>

  DD stops, and there are lots of partial halt deciders that will decide
that particular input correctly.  PO's DD isn't "undecidable".

>
I hear what you're saying (or at least I see what you typed), but if DD's
result is so decidable, how come his decider can't correctly decide?

 This is just a misunderstand about terms.  The fact that some program
gets the answer wrong does not mean that this case is not (correctly)
decidable.

I beg you to forgive a little levity. I was just rather amused that a program so utterly devoted to overturning a decidability proof seems quite unable to make a decision.
--
Richard Heathfield
Email: rjh at cpax dot org dot uk
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