At the most fundamental level:
All Turing machines only compute the mapping
from input finite strings to some value.
Turing machine Deciders are a subset of this
where the value indicates accept or reject a
finite string by some criterion measure.
A further elaboration of this comes from the
notion of computable functions and Rice's
Theorem:
Turing machine deciders compute functions from
*finite string inputs* to {accept, reject} values
according to whether the input has a syntactic
property or specifies a semantic property.
Turing machine deciders only report on the behavior
of Turing machines indirectly through the proxy of
finite string inputs. *This key detail has been ignored*
At the most fundamental level:
All Turing machines only compute the mapping
from input finite strings to some value.
Turing machine Deciders are a subset of this
where the value indicates accept or reject a
finite string by some criterion measure.
On 13/12/2025 16:44, olcott wrote:
At the most fundamental level:
All Turing machines only compute the mapping
from input finite strings to some value.
Turing machine Deciders are a subset of this
where the value indicates accept or reject a
finite string by some criterion measure.
I continue to reject the use of "accept" and "reject" here. And I also
reject the use of "indicates" wrt to them.
There's no good reason to suppose this is about grammars and strings
rather than propositions about programs. To the extent that they might
be isomorphic you need to introduce the notion of grammars and string acceptance by them to give "accept" and "reject" and "indicates" the
correct meaning.
On 12/13/25 11:44 AM, olcott wrote:
At the most fundamental level:
All Turing machines only compute the mapping
from input finite strings to some value.
Turing machine Deciders are a subset of this
where the value indicates accept or reject a
finite string by some criterion measure.
A further elaboration of this comes from the
notion of computable functions and Rice's
Theorem:
Turing machine deciders compute functions from
*finite string inputs* to {accept, reject} values
according to whether the input has a syntactic
property or specifies a semantic property.
Turing machine deciders only report on the behavior
of Turing machines indirectly through the proxy of
finite string inputs. *This key detail has been ignored*
So, if the function isn't "Computable", it is still a Function, but no Turing Machine (or equivalent) can compute it.
On 12/13/2025 1:14 PM, Richard Damon wrote:
On 12/13/25 11:44 AM, olcott wrote:
At the most fundamental level:
All Turing machines only compute the mapping
from input finite strings to some value.
Turing machine Deciders are a subset of this
where the value indicates accept or reject a
finite string by some criterion measure.
A further elaboration of this comes from the
notion of computable functions and Rice's
Theorem:
Turing machine deciders compute functions from
*finite string inputs* to {accept, reject} values
according to whether the input has a syntactic
property or specifies a semantic property.
Turing machine deciders only report on the behavior
of Turing machines indirectly through the proxy of
finite string inputs. *This key detail has been ignored*
So, if the function isn't "Computable", it is still a Function, but no
Turing Machine (or equivalent) can compute it.
There seems to be no such thing as uncomputable
functions when Turing machines are construed
entirely in terms of finite string rewrite rules.
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