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

On 14/03/2025 11:02, joes wrote:

Am Thu, 13 Mar 2025 20:48:09 -0500 schrieb olcott:

On 3/13/2025 4:21 PM, Richard Heathfield wrote:

On 13/03/2025 20:48, dbush wrote:

<snip>

Only because one changes the code that DD runs and one doesn't

>
It hardly matters. Either his emulation faithfully and correctly
establishes and reports (for EVERY program anyone cares to feed it) the
actual halting behaviour exhibited by the program it's emulating, or it
doesn't.
>

That everyone expects the behavior of the directly executed DDD to be
the same as DDD correctly emulated by HHH1 is verified as a factually
correct expectation.
That everyone expects the behavior of the directly executed DDD to be
the same as DDD correctly emulated by HHH is verified as a factually
incorrect expectation.

A simulation should not differ from the actual execution. Why should it?

Why indeed? But of course it doesn't matter. If the simulation correctly reports the outcome, it factors itself out of the equation and Turing's logic stands. And if it doesn't, it gives broken results that cannot be trusted to support a conclusion.

If it doesn't, it doesn't, and it's a lot of fuss over nothing.
But if it /does/, then we're right back at Turing's proof, because a
working emulator is just another way of running the code, and is
therefore superfluous to requirements. It adds nothing to the debate,
because we can just run the code and get the same answer the emulator
would provide.
>

For the first time in the history of mankind it proves that a simulation
of a virtual machine according to the semantics of this machine language
DOES NOT ALWAYS HAVE THE SAME BEHAVIOR AS THE DIRECT EXECUTION OF THIS
SAME MACHINE

Bold claim. How does that make sense?

Well, it doesn't, but you weren't expecting it to, were you?
<snip>
--
Richard Heathfield
Email: rjh at cpax dot org dot uk
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