Re: The simple essence of Proof Theoretic Semantics

On 2026-07-02 dbush wrote:

> The halting problem doesn't actually have self reference, as
 > algorithms can be copied as in the below example of algorithm D:
> 
> void D(ptr *I)
> {
>      // algorithm D; input: I
>      ptr *X = D;
>      ptr *Y = I;
>      int result;
>      {
>          // algorithm H; inputs: X,Y
>          result = 0;
>      }
>      if (result == 1) {
>          while (1);
>      }
> }
> 
> Which is the counter example input to algorithm H:
> 
> int H(ptr *X, ptr *Y)
> {
>      int result;
>      {
>          // algorithm H; inputs: X,Y
>          result = 0;
>      }
>      return result;
> }

On 03/07/2026 18:36, olcott wrote:
> On 7/3/2026 4:22 AM, Mikko wrote:
>> On 02/07/2026 17:51, olcott wrote:
>>>
>>> Do you know enough about C to understand that
>>> dbush example was foolish nonsense when proposed
>>> to show the halting problem counter-example?
>>
>> It is a valid example of a C program. It was present as a part of a
>> claim about you, and your response was the false claim that "That
>> is just nonsense". Later in the discussion you offer more evidence
>> to support his claim.
> 
> His halt decider did not look at its input.

For every possible input his H halts and returns either 0 for false
or 1 for true. Therefore his H is a decider. It return 0 for D
although D halts so the decider H is not a halt decider.

> His input merely halted and did not call
> this halt decider. He used {} in a way that
> made no sense in C.

His use of {} is perfectly correct by C rules and as meaningful ans
usually. Your false claim (not shown above) is false.

-- 
Mikko