Re: Every sufficiently competent C programmer knows --- Semantic Property of Finite String

On 3/14/2025 11:51 AM, olcott wrote:

On 3/14/2025 10:04 AM, wij wrote:

On Fri, 2025-03-14 at 09:35 -0500, olcott wrote:>>

void DDD()
{
    HHH(DDD);
    return;
}
>
DDD correctly simulated by HHH cannot possibly reach
its own "return" instruction in any finite number of
correctly simulated steps.
>
That you are clueless about the semantics of something
as simple as a tiny C function proves that you are not
competent to review my work.
>

>
https://en.wikipedia.org/wiki/Halting_problem
In computability theory, the halting problem is the problem of determining, from a description of an
arbitrary computer program and an input, whether the program will finish running, or continue to run
forever.
>
That means: H(D)=1 if D() halts and H(D)=0 if D() does not halt.
>
But, it seems you don't understand English, as least as my level, ....
>
>
>

 void DDD()
{
   HHH(DDD);
   return;
}
 The only difference between HHH and HHH1 is that they are
at different locations in memory. DDD simulated by HHH1
has identical behavior to DDD() directly executed in main().
 The semantics of the finite string input DDD to HHH specifies

That it will halt when executed directly

 The semantics of the finite string input DDD to HHH1 specifies

That it will halt when executed directly

 When HHH(DDD) reports on the behavior that its input finite
string specifies it can only correctly report non-halting.
 

False.  The finite string specifies a computation that halts when executed directly, as per the requirements:
Given any algorithm (i.e. a fixed immutable sequence of instructions) X described as <X> with input Y:
A solution to the halting problem is an algorithm H that computes the following mapping:
(<X>,Y) maps to 1 if and only if X(Y) halts when executed directly
(<X>,Y) maps to 0 if and only if X(Y) does not halt when executed directly

When HHH(DDD) is required to report on behavior other than
the behavior that its finite string specifies HHH is not
a decider thus not a halt decider.
 

In other words, you're claiming an H where H(X) reports what X will do when executed directly is not a decider.  What term would you use to describe it, then?

All deciders are required to compute the mapping from
their input finite string to the semantic or syntactic property
that this string specifies. Deciders return true when this
string specifies this property otherwise they return false.
 

And the finite string DDD specifies a computation that halts when executed directly.