(P → ((P → Q) ∧ (Q → R))) ↔ {P, P → Q, Q → R} ⊢ R
(1) P & P → Q [rewritten as] Q
(2) Q & Q → R [rewritten as] R
(3) ∴ {P, P → Q, Q → R} ⊢ R
The above example provides the logical equivalence of the
LHS to the RHS.
The LHS is a set of premises from which the RHS conclusion
is derived.
Truth Table of the above formal proof:
(P → ((P → Q) ∧ (Q → R))) ↔ {P, P → Q, Q → R} ⊢ R
---------------------------------------------------
_0_________?__?______?____?__1______?_____?__0__?
_1_________1__1______1____1__1______1_____1__1__1
I'll cut to the chase... peteolcott <peteo...@gmail.com> writes: <snip>
So when H^ evaluates Wm Wm (for clarity we will call Wm_1 and Wm_2) the execution trace of Wm_1 indicates that it makes a copy of Wm_2 which for clarity we will call Wm_3. The next step of the execution trace of Wm_1 indicates that it begins its own evaluation execution trace of Wm_2 Wm_3. The execution trace of Wm_2 indicates that it makes a copy of Wm_3 which for clarity we will call Wm_4.
None of the Wm have an execution trace. They are stings in the alphabet of the TM H (and H^). The only thing that can have has any "execution trace" is H^ and we have no idea what it does after copying the tape other than it behaves like some other machine called H. You don't understand Linz's notation, and you don't understand what H^ is. And, as usual, you a confusing machines with representations of machines. <snip>
Maybe this much more precise wording will answer your prior objections.
On Monday, January 15, 2018 at 10:13:42 PM UTC-8, Pete Olcott wrote:
On 3/15/2017 12:12 PM, Ben Bacarisse wrote: I'll cut to the chase... peteolcott <pete...@gmail.com> writes: <snip> So when H^ evaluates Wm Wm (for clarity we will call Wm_1 and Wm_2) the execution trace of Wm_1 indicates that it makes a copy of Wm_2 which for clarity we will call Wm_3. The next step of the execution trace of Wm_1 indicates that it begins its own evaluation execution trace of Wm_2 Wm_3. The execution trace of Wm_2 indicates that it makes a copy of Wm_3 which for clarity we will call Wm_4. None of the Wm have an execution trace. They are stings in the alphabet of the TM H (and H^). The only thing that can have has any "execution trace" is H^ and we have no idea what it does after copying the tape other than it behaves like some other machine called H. You don't understand Linz's notation, and you don't understand what H^ is. And, as usual, you a confusing machines with representations of machines. <snip> Maybe this much more precise wording will answer your prior objections. http://liarparadox.org/HP_Infinite_Recursion.pdf
Yes, Ĥ never halts, which means that it cannot say that it never halts..
George Greene <gre...@email.unc.edu> writes: <snip>The ACTUAL correction would read something like qx Wm Wm ⊢* Ĥ y1 qn y2 , since Linz's notation ALWAYS starts with the state where you are beginning. You are just assuming continuation from the previous/last state, which is correct, but again, the question is HOW TO WRITE it clearly, and Linz just fails massively.Linz has a notation that could have been used to clear this up but it's even more cumbersome: q_(A,0) for state 0 of machine A. And while it makes it clear what states belong to which machine that also obscures the fact the all the machines in the construction share a lot of states and transitions. Do you say that q_(H,i) = q_(H',i) for all n states of H, or do you allow them to be distinct provided the state transitions are preserved by the correspondence between them? It makes no odds, of course, since all that matters is the behaviour, but when talking about states and transitions and traces you have to say one way or the other. Basically, the description is at the wrong level. The level that matters is of computations and compositions of computations.
http://liarparadox.org/HP_Infinite_Recursion.pdf
// zoom in to see high resolution detail
Ĥ
is being applied to its own TM description ŵ.
// See top of page 320
// Definition of Ĥ (page 319) with
detail
added
from Figure 12.2
// and Correction
(no finite state machine can have two start states):
// q0
changed to qx
Final
Definition of Ĥ after correction and added detail
q0 Wm ⊢* Ĥ qx Wm Wm ⊢* Ĥ qy ∞ // Correction and Detail
q0
Wm ⊢* Ĥ qx
Wm Wm ⊢* Ĥ y1 qn y2 // Correction
The lambda calculus works at the right level for this, but there is so much more technical material to cover before students feel that a lambda form really encapsulates the idea of an effective procedure that any advantage this presentation may have is undone. TM's are so simple to explain and so obviously capture the basic idea of doing something mechanically that they are the natural choice. What is needed is a presentation that uses TMs but that works at a level higher than the states and the transitions. You can make it formal, but you do that when explaining general constructs like
peteolcott <petero...@gmail.com> writes:On Thursday, January 18, 2018 at 7:04:52 PM UTC-6, Ben Bacarisse wrote:peteolcott writes:On Tuesday, January 16, 2018 at 7:09:26 PM UTC-6, Ben Bacarisse wrote:
George Greene writes: <snip>The ACTUAL correction would read something like qx Wm Wm ⊢* Ĥ y1 qn y2 , since Linz's notation ALWAYS starts with the state where you are beginning. You are just assuming continuation from the previous/last state, which is correct, but again, the question is HOW TO WRITE it clearly, and Linz just fails massively.Linz has a notation that could have been used to clear this up but it's even more cumbersome: q_(A,0) for state 0 of machine A. And while it makes it clear what states belong to which machine that also obscures the fact the all the machines in the construction share a lot of states and transitions. Do you say that q_(H,i) = q_(H',i) for all n states of H,
That would be a neat trick since H and H' have mutually exclusive states.No, H and H' may have non-intersecting state sets or they may not have.If a cat is defined to be an animal you are no longer free to define a cat as a pile of bricks. H is defined with two final states, H' is and adapted form of H where one of these final states has been converted into an infinite loop.You can define H' either way. The fact that you can't see this is very telling.That is analogous to defining a cat as a pile of bricks, thus positing this absurdity you are showing your lack of integrity.No. You analogy reveals you don't understand either what I wrote or what a TM is. Important facts about cats (such as they are not dogs) do not depend on the names given to their hairs.The states themselves have almost no significance for TMs. What matters is the state transition function.state ((qy)) that was converted to (qy) ∞, both transitions having a defined semantics, equivalent to Boolean True.No again. The sates have no semantics of any significance. We can call them the green and the purple states. The theorem then tells us of the non-existence of a TM that can decide which strings encode those TMs that enter a purple state (or, for that matter, a green state).So all your hem-hawing to be disagreeable makes you disingenuous. You could understand and confirm what I say you prefer to be disagreeable even a the cost of truth.No. You are completely at sea. Mainly because you started with a false conclusion as your premise -- halt deciding *must* be "wrong" in some way -- and you have wasted more than a decade trying to find some way of saying that that makes sense.
peteolcott <petero...@gmail.com> writes:
On Wednesday, January 24, 2018 at 8:38:12 PM UTC-6, Ben Bacarisse wrote:
peteolcott writes: <snip>So how would be formalize the semantics of Halts when we are going fully David Hilbert? ∃x ∈ Finite_Strings & x ∈ Turing_Machine_Descriptions ∀y ∈ Finite Strings & y ∈ Turing_Machine_Descriptions ∀z ∈ Finite_Strings Halts(x, y, z) or perhaps this ∃x ∈ Turing_Machine_Descriptions ∀y ∈ Turing_Machine_Descriptions ∀z ∈ Finite_Strings Halts(x, y, z)There is not much to choose between them. Both speak volumes.So you are back to simply being disrespectful again?You have repeatedly called me a liar. What makes you think you deserve any respect from me (or from anyone else for that matter)?
Linz
page Bottom of page 319
q0
Wm ⊢* Ĥ q0
Wm Wm ⊢* Ĥ ∞
q0
Wm ⊢* Ĥ q0
Wm Wm ⊢* Ĥ y1 qn y2
My correction
q0 ŵ ⊢* Ĥ qx ŵ ŵ ⊢* Ĥ qy ∞
Formalized
as: SentenceF(G)
∧ ~ProvableF(G)
∧ ~RefutableF(G)
Proving
that the above sentence is false refutes the 1931 GIT.
H^ must examine what w^ does this requires an examination of what w^2 does which requires an examination of what w^3 does...That is not what the notation says.
peteolcott <petero...@gmail.com> writes:
On Tuesday, February 6, 2018 at 9:34:06 AM UTC-6, Ben Bacarisse wrote:
Definition of Turing Machine Ĥx (Ĥ - loop)peteolcott writes: <snip>H simply recognizes the Pathological-Self-Reference(Olcott 2004) of [H^][H^] and transitions to its ((qn)) state indicating that it rejects the input on the basis that it specifies an infinitely recursive evaluation sequence.There is a theorem that proves this is not possible. Inputs with what you call PSR are not a decidable set. No TM can spot them all.Try and provide a single counter-example that meets this spec: An expression of language (formal or otherwise) has the property of Pathological Self-Reference(Olcott 2004) when-so-ever the self-reference of this expression prevents this expression from being evaluated as True or False.That's a definition (albeit not a very good one). Do you even know what a counter example is? How can there be a counter example to a definition?You claim that it has been proven to be undecidable so it should not be very hard for someone understanding this proof to come up with a single valid counter-example that refutes my claim to be able to always detect and report PSR.Oh dear. Of course I can't. I wrote, and re-wrote, and then re-wrote again several answers to this but in the end I lost heart and I've just deleted the text. You don't know what a counter example is, or what a decidable set is, and I don't think I have the ability (and certainly not the inclination) to teach you what they are. I've told you why your objection to the classic halting theorem proof is wrong. I don't think I can do more. I will however, retract my claim about PSR not being decidable. I fear it is a movable feast and it seems likely to me (from the current rather vague wording) that there are no examples of it relating to halting. That would make TMD/input pairs with PSR trivially decidable. Then again, maybe it means something else when applied to halting problems and it really isn't decidable. I can't tell and I don't care. I will say only this: if Rice's theorem would apply to it then it is not decidable. <snip>
http://liarparadox.org/index.php/2018/01/18/refutation-of-the-halting-problem-proof/http://LiarParadox.org/HP_Infinite_Recursion.pdf As this page 319 of An Introduction to Formal Languages and Automata by Peter Linz 1990 indicates From H' we construct another Turing machine H-Hat. This new machine takes as input Wm, copies it then behaves exactly like H'. q0 Wm |-* H-Hat q0 Wm Wm... Page 320 indicates that we apply H-Hat to itself as input. The problem is that every H-Hat needs a pair of inputs. H-Hat takes an H-Hat as input and copies it so that it can analyze how its input H-hat would analyze the copy of H-Hat that it just made. The input H-Hat would have to copy its own input H-Hat so that it can analyze what its own input H-Hat would do on its own input, on and on forever... Copyright 2016 and 2017 Pete Olcott.