Re: Coordinate time vs Proper time

['Brent Meeker' via Everything List]

On 5/22/2020 9:48 PM, Alan Grayson wrote:



On Friday, May 22, 2020 at 9:05:23 PM UTC-6, Brent wrote:



On 5/22/2020 6:26 PM, Alan Grayson wrote:



On Monday, May 18, 2020 at 3:28:40 PM UTC-6, Alan Grayson wrote:

Suppose the universe is a hyper-sphere, not expanding, and an
observer travels on a closed loop and returns to his spatial
starting point. His elapsed or proper time will be finite,
but what is his coordinate time at the end of the journey? 
TIA, AG


It's not a dumb question IMO. If you circumnavigate a spherical
non-expanding universe, what happens to coordinate time at the
end of the journey? Does something update the time coordinate? Or
does it somehow miraculously(?) remain fixed? TIA, AG


Are you supposing the universe is a 3-sphere?  In that case It's
just like going around a circle.  The degree marks on the circle
are coordinates, they have no physical meaning except to label
points.  So if you walk around the circle you measure a certain
distance (proper time) but come back to the same point.

Or are you supposing it's a 4-sphere so that all geodesics are
closed time-like curves?  I don't know how that would work.  I
don't think there's any solution of that form to Einstein's equations.

Brent


I'm supposing a 4-sphere and (I think) closed time-like curves. The 
traveler returns presumably to his starting position, but is the time 
coordinate unchanged? AG


I don't think there's any very sensible answer in that case.  Goedel 
showed there can be solutions with closed time-like curves if the 
universe is rotating.  But solutions of GR don't have any dynamic 
connection to matter and the entropy of matter.  In the same spirit 
there could be a solution to quantum field theory that was close around 
the time like curve...in which case you'd experience "Groundhog 
Day"...including your thoughts.


Brent

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Re: Coordinate time vs Proper time

[Alan Grayson]

On Friday, May 22, 2020 at 9:05:23 PM UTC-6, Brent wrote:
>
>
>
> On 5/22/2020 6:26 PM, Alan Grayson wrote:
>
>
>
> On Monday, May 18, 2020 at 3:28:40 PM UTC-6, Alan Grayson wrote: 
>>
>> Suppose the universe is a hyper-sphere, not expanding, and an observer 
>> travels on a closed loop and returns to his spatial starting point. His 
>> elapsed or proper time will be finite, but what is his coordinate time at 
>> the end of the journey?  TIA, AG
>>
>
> It's not a dumb question IMO. If you circumnavigate a spherical 
> non-expanding universe, what happens to coordinate time at the end of the 
> journey? Does something update the time coordinate? Or does it somehow 
> miraculously(?) remain fixed? TIA, AG
>
>
> Are you supposing the universe is a 3-sphere?  In that case It's just like 
> going around a circle.  The degree marks on the circle are coordinates, 
> they have no physical meaning except to label points.  So if you walk 
> around the circle you measure a certain distance (proper time) but come 
> back to the same point.
>
> Or are you supposing it's a 4-sphere so that all geodesics are closed 
> time-like curves?  I don't know how that would work.  I don't think there's 
> any solution of that form to Einstein's equations.
>
> Brent
>

I'm supposing a 4-sphere and (I think) closed time-like curves. The 
traveler returns presumably to his starting position, but is the time 
coordinate unchanged? AG 

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Re: Coordinate time vs Proper time

['Brent Meeker' via Everything List]

On 5/22/2020 6:26 PM, Alan Grayson wrote:



On Monday, May 18, 2020 at 3:28:40 PM UTC-6, Alan Grayson wrote:

Suppose the universe is a hyper-sphere, not expanding, and an
observer travels on a closed loop and returns to his spatial
starting point. His elapsed or proper time will be finite, but
what is his coordinate time at the end of the journey?  TIA, AG


It's not a dumb question IMO. If you circumnavigate a spherical 
non-expanding universe, what happens to coordinate time at the end of 
the journey? Does something update the time coordinate? Or does it 
somehow miraculously(?) remain fixed? TIA, AG


Are you supposing the universe is a 3-sphere?  In that case It's just 
like going around a circle.  The degree marks on the circle are 
coordinates, they have no physical meaning except to label points. So if 
you walk around the circle you measure a certain distance (proper time) 
but come back to the same point.


Or are you supposing it's a 4-sphere so that all geodesics are closed 
time-like curves?  I don't know how that would work.  I don't think 
there's any solution of that form to Einstein's equations.


Brent

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Re: "Shape" of the universe

[Alan Grayson]

On Tuesday, May 19, 2020 at 11:18:15 PM UTC-6, Alan Grayson wrote:
>
>
>
> On Tuesday, May 19, 2020 at 6:26:08 PM UTC-6, Lawrence Crowell wrote:
>>
>> You cannot of course circumnavigate the spatial manifold of the universe. 
>> Anything beyond the cosmological horizon moves away faster than you can 
>> ever catch up. It is a bit like the part in the movie The Shining with Jack 
>> Nicholson where the hotel hallway expanded faster than he could run. If we 
>> could though observe this, say analogous to Jack Nicholson in the film, 
>> there would be optical effects. The spatial manifold could be a k = 1 
>> closed or k = -1 hyperbolic or the dodecahedral tessellated universe of 
>> Poincaré. Yet so far data is not forthcoming.
>>
>> A Planck energy of quanta, say a UV graviton, could have causal influence 
>> on us is it expands to the cosmological horizon or near so. The B-modes of 
>> inflation, which are still being pursued, represent Planck units redshifted 
>> to some appreciable scale comparable to the cosmological horizon. This is a 
>> z factor z = 10^{10}ly/ℓ_p = 6.3×10^{60}, where taking the nat-log of this 
>> and multiplying by the horizon scale 1.3×10^{10}ly we get 1.8×10^{12}ly. 
>> The furthest out anything can have traversed at the speed of light to reach 
>> is from that distance and from the earliest near Planck time in the 
>> universe. What this means is the source or emitter of this graviton was 
>> early on close to our region and the source is not that incredible distance 
>> away. 
>>
>> LC
>>
>
> Is this estimate reasonable, also from  
>
> https://www.forbes.com/sites/startswithabang/2020/05/19/would-a-long-journey-through-the-universe-bring-us-back-to-our-starting-point/#fe376fef6c50
>
>
> The appearance of different angular sized of fluctuations in the CMB 
> results in different spatial curvature scenarios. Presently, the Universe 
> appears to be flat, but we have only measured down to about the 0.4% level. 
> At a more precise level, we may discover some level of intrinsic curvature, 
> after all, but what we've observed is enough to tell us that if the 
> Universe is curved, it's only curved on scales that are ~(250)^3 times (or 
> more than 15 million times) larger than our presently-observable Universe 
> is.
>
> AG
>

What I'm asking is whether, based on current measurements, if the universe 
is curved, can we conclude that the universe is *15 million times larger* 
than our presently observable universe? TIA, AG 

>
>
>
>
>
>  
>
>>
>>
>> On Tuesday, May 19, 2020 at 1:41:45 AM UTC-5, Philip Thrift wrote:
>>
>>>
>>>
>>> *Would traveling out in a "straight" line bring you back to where you 
>>> started?*
>>>
>>>
>>> https://www.forbes.com/sites/startswithabang/2020/05/19/would-a-long-journey-through-the-universe-bring-us-back-to-our-starting-point/#1781c2ccf6c5
>>>
>>> In the writer's (Ethan Siegel's) *opinion*:
>>>
>>>
>>> On a cosmic scale, there is no indication that the Universe is anything 
>>> other than infinite and flat. There is no evidence that features in one 
>>> region of space also appear in any other well-separated region, nor is 
>>> there evidence of a repeating pattern in the Universe's large-scale 
>>> structure or the Big Bang's leftover glow. The only way we know of to turn 
>>> a freely moving object around is via gravitation slingshot, not from cosmic 
>>> curvature.
>>>
>>> And yet, it's a legitimate possibility that the Universe may, in fact, 
>>> be finite in extent, but larger than our observations can currently take 
>>> us. As the Universe unfolds over the coming billions of years, more and 
>>> more of it (about 135% more, by volume) will become visible to us. If 
>>> there's any hint that a long-distance journey would bring us back to our 
>>> starting point, that's the only place we'll ever find it. Our only hope for 
>>> discovering a finite but traversible Universe lies, quite ironically, in 
>>> our far distant future.
>>>
>>> @philipthrift
>>>
>>

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Re: Coordinate time vs Proper time

[Alan Grayson]

On Monday, May 18, 2020 at 3:28:40 PM UTC-6, Alan Grayson wrote:
>
> Suppose the universe is a hyper-sphere, not expanding, and an observer 
> travels on a closed loop and returns to his spatial starting point. His 
> elapsed or proper time will be finite, but what is his coordinate time at 
> the end of the journey?  TIA, AG
>

It's not a dumb question IMO. If you circumnavigate a spherical 
non-expanding universe, what happens to coordinate time at the end of the 
journey? Does something update the time coordinate? Or does it somehow 
miraculously(?) remain fixed? TIA, AG 

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Re: STEP 3

['Brent Meeker' via Everything List]

On 5/22/2020 1:48 PM, Jason Resch wrote:



On Fri, May 22, 2020 at 3:27 PM 'Brent Meeker' via Everything List 
> wrote:




On 8/4/2019 10:44 AM, Jason Resch wrote:



On Friday, August 2, 2019, 'Brent Meeker' via Everything List
mailto:everything-list@googlegroups.com>> wrote:



On 8/2/2019 1:06 PM, Jason Resch wrote:



On Fri, Aug 2, 2019 at 1:40 PM 'Brent Meeker' via Everything
List mailto:everything-list@googlegroups.com>> wrote:



On 8/2/2019 11:03 AM, Jason Resch wrote:
> It is like Saibal Mitra said, the person he was when
he was 3 is
> dead.  Too much information was added to his brain. 
If his 3 year old
> self were suddenly replaced with his much older self,
you would
> conclude the 3 year old was destroyed, but when
gradual changes are
> made, day by day, common-sense and convention
maintains that the
> 3-year-old was not destroyed, and still lives. This is
the
> inconsistency of continuity theories.

On the contrary I'd say it illustrates the consistency
of causal
continuity theories.


Your close friend walks into a black box, and emerges 1 hour
later.

In case A, he was destroyed in a discontinuous way, and a
new version of that person was formed having the mind of
your friend as it might have been 1 hour later.
In case B, he sat around for an hour before emerging.

You later meet up with the entity who emerges from this
black box for coffee.

From your point of view, neither case A nor B is physically
distinguishable.  Yet under your casual continuity theory,
your friend has either died or survived entering the black
box.  You have no way of knowing if the entity you are
having coffee with is your friend or not.   Is this a
legitimate and consistent way of looking at the world?


Did the black box take A's information in order to copy him,
or did it make a copy accidentally.


Would that change the result?


Holevo's theorem says it's impossible to copy A's state.


It's a thought experiment. Do you think the quantum state is relevant? 
One typically doesn't track of the quantum state of their friend's 
atoms and use that information as part of their recognition process.






Incidentally, my not knowing the difference between two
things is not very good evidence that they are the same.


That there's no physical experiment, even in principle, that
could differentiate the two cases, I take as evidence that
notions of identity holding there to be a difference are illusory.


But you haven't postulated a case in which it is impossible to
differentiate the two cases.  It's not clear what degree of
differentiation is relevant.


If Holebo's theorem remains fundamental problems, then let's move 
everything into virtual reality, and repeat the experiment.


In one case your friend's mind file is deleted and restored from a 
backup, and in another he continued without interruption. Do not the 
same conclusions I suggest follow?


So you're postulating that your friend has been duplicated but in a way 
that you have no way of knowing.  And then you ask, "Is this a 
legitimate and consistent way of looking at the world?"  I guess I don't 
understand the question.  If you have no way of knowing, then you don't 
know...ex hypothesi.


Brnet

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Re: STEP 3

[Bruce Kellett]

On Sat, May 23, 2020 at 6:48 AM Jason Resch  wrote:

>
> If Holebo's theorem remains fundamental problems, then let's move
> everything into virtual reality, and repeat the experiment.
>
> In one case your friend's mind file is deleted and restored from a backup,
> and in another he continued without interruption. Do not the same
> conclusions I suggest follow?
>


Thought experiments in virtual reality (where you get to make up the laws
of physics) have no relevance for the world we observe.

Bruce

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Re: "magic" (in programming)

[spudboy100 via Everything List]

Yes indeed! Charles Stross's Series, The Laundry Files is an extension of 
Lovecraft mixed with La Carre' + Terry Pratchett. 
" As a branch of applied mathematics, magic was practiced on an ad-hoc basis 
prior to its systematization by Alan Turing in the 1940s. Wartime efforts 
combined the approach of GCHQ (cryptanalysis, applied computational demonology) 
and SOE (sabotage operations, combat philosophy) and led to the establishment 
of the post-war secret agency documented in these classified 
publications.Members of staff assigned to Active Operations are required to 
maintain a journal describing their operations, so that in event of their death 
or assimilation by an extradimensional nightmare their knowledge is not lost to 
the organization. As a new recruit you are encouraged to familiarize yourself 
with these classified sources: they’re an invaluable learning resource and the 
following reading list may prove 
helpful."https://www.tor.com/2018/10/30/a-primer-on-charles-strosss-the-laundry-files/



-Original Message-
From: Philip Thrift 
To: Everything List 
Sent: Fri, May 22, 2020 7:10 am
Subject: "magic" (in programming)



The term "magic" implies that the hidden complexity is at least in principle 
understandable, in contrast to black magic and deep magic (see Variants), which 
describe arcane techniques that are deliberately hidden or extremely difficult 
to understand. 


https://en.wikipedia.org/wiki/Magic_(programming)

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Re: STEP 3

[Jason Resch]

On Fri, May 22, 2020 at 3:27 PM 'Brent Meeker' via Everything List <
everything-list@googlegroups.com> wrote:

>
>
> On 8/4/2019 10:44 AM, Jason Resch wrote:
>
>
>
> On Friday, August 2, 2019, 'Brent Meeker' via Everything List <
> everything-list@googlegroups.com> wrote:
>
>>
>>
>> On 8/2/2019 1:06 PM, Jason Resch wrote:
>>
>>
>>
>> On Fri, Aug 2, 2019 at 1:40 PM 'Brent Meeker' via Everything List <
>> everything-list@googlegroups.com> wrote:
>>
>>>
>>>
>>> On 8/2/2019 11:03 AM, Jason Resch wrote:
>>> > It is like Saibal Mitra said, the person he was when he was 3 is
>>> > dead.  Too much information was added to his brain.  If his 3 year old
>>> > self were suddenly replaced with his much older self, you would
>>> > conclude the 3 year old was destroyed, but when gradual changes are
>>> > made, day by day, common-sense and convention maintains that the
>>> > 3-year-old was not destroyed, and still lives. This is the
>>> > inconsistency of continuity theories.
>>>
>>> On the contrary I'd say it illustrates the consistency of causal
>>> continuity theories.
>>>
>>>
>> Your close friend walks into a black  box, and emerges 1 hour later.
>>
>> In case A, he was destroyed in a discontinuous way, and a new version of
>> that person was formed having the mind of your friend as it might have been
>> 1 hour later.
>> In case B, he sat around for an hour before emerging.
>>
>> You later meet up with the entity who emerges from this black box for
>> coffee.
>>
>> From your point of view, neither case A nor B is physically
>> distinguishable.  Yet under your casual continuity theory, your friend has
>> either died or survived entering the black box.  You have no way of knowing
>> if the entity you are having coffee with is your friend or not.   Is this a
>> legitimate and consistent way of looking at the world?
>>
>>
>> Did the black box take A's information in order to copy him, or did it
>> make a copy accidentally.
>>
>
> Would that change the result?
>
>
> Holevo's theorem says it's impossible to copy A's state.
>

It's a thought experiment. Do you think the quantum state is relevant? One
typically doesn't track of the quantum state of their friend's atoms and
use that information as part of their recognition process.



>
>
>
>>
>>
>> Incidentally, my not knowing the difference between two things is not
>> very good evidence that they are the same.
>>
>>
>>
>
> That there's no physical experiment, even in principle, that could
> differentiate the two cases, I take as evidence that notions of identity
> holding there to be a difference are illusory.
>
>
> But you haven't postulated a case in which it is impossible to
> differentiate the two cases.  It's not clear what degree of differentiation
> is relevant.
>

If Holebo's theorem remains fundamental problems, then let's move
everything into virtual reality, and repeat the experiment.

In one case your friend's mind file is deleted and restored from a backup,
and in another he continued without interruption. Do not the same
conclusions I suggest follow?

Jason

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Re: STEP 3

['Brent Meeker' via Everything List]

On 8/4/2019 10:44 AM, Jason Resch wrote:



On Friday, August 2, 2019, 'Brent Meeker' via Everything List 
> wrote:




On 8/2/2019 1:06 PM, Jason Resch wrote:



On Fri, Aug 2, 2019 at 1:40 PM 'Brent Meeker' via Everything List
mailto:everything-list@googlegroups.com>> wrote:



On 8/2/2019 11:03 AM, Jason Resch wrote:
> It is like Saibal Mitra said, the person he was when he was
3 is
> dead.  Too much information was added to his brain.  If his
3 year old
> self were suddenly replaced with his much older self, you
would
> conclude the 3 year old was destroyed, but when gradual
changes are
> made, day by day, common-sense and convention maintains
that the
> 3-year-old was not destroyed, and still lives. This is the
> inconsistency of continuity theories.

On the contrary I'd say it illustrates the consistency of causal
continuity theories.


Your close friend walks into a black  box, and emerges 1 hour later.

In case A, he was destroyed in a discontinuous way, and a new
version of that person was formed having the mind of your friend
as it might have been 1 hour later.
In case B, he sat around for an hour before emerging.

You later meet up with the entity who emerges from this black box
for coffee.

From your point of view, neither case A nor B is physically
distinguishable.  Yet under your casual continuity theory, your
friend has either died or survived entering the black box.  You
have no way of knowing if the entity you are having coffee with
is your friend or not.   Is this a legitimate and consistent way
of looking at the world?


Did the black box take A's information in order to copy him, or
did it make a copy accidentally.


Would that change the result?


Holevo's theorem says it's impossible to copy A's state.




Incidentally, my not knowing the difference between two things is
not very good evidence that they are the same.


That there's no physical experiment, even in principle, that could 
differentiate the two cases, I take as evidence that notions of 
identity holding there to be a difference are illusory.


But you haven't postulated a case in which it is impossible to 
differentiate the two cases.  It's not clear what degree of 
differentiation is relevant.


Brent

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Re: The size of the universe

[Jason Resch]

On Fri, May 22, 2020 at 9:23 AM Bruno Marchal  wrote:

>
> On 21 May 2020, at 21:43, Jason Resch  wrote:
>
>
>
> On Thu, May 21, 2020 at 1:33 PM Bruno Marchal  wrote:
>
>>
>> On 20 May 2020, at 18:45, Jason Resch  wrote:
>>
>>
>>
>> On Wed, May 20, 2020 at 7:05 AM Bruno Marchal  wrote:
>>
>>>
>>> On 19 May 2020, at 05:20, Jason Resch  wrote:
>>>
>>> I recently wrote an article on the size of the universe and the scope of
>>> reality:
>>> https://alwaysasking.com/how-big-is-the-universe/
>>>
>>> It's first of what I hope will be a series of articles which are
>>> largely inspired by some of the conversations I've enjoyed here. It covers
>>> many topics including the historic discoveries, the big bang, inflation,
>>> string theory, and mathematical realism.
>>>
>>>
>>>
>>>
>>> It has not been proved that the decimal expansion of PI contains all
>>> (finite codes of all) sequences.
>>>
>>
>> I understand that Pi is proven to be normal,
>>
>>
>>
> (Oops I meant to say "Pi is not proven to be normal" somehow I deleted the
> *not* while refactoring the sentence)
>
>
> OK.
>
>
>
>
>
>>
>> But that is not the case. Pi win all experimental test, but the normality
>> of basically all irrational numbers are open problems. It is generally
>> conjectured that they are all normal.
>> For the Champernow number, the normality is easy to prove, but it has
>> been build that way.
>>
>>
>>
>> but is it true for the irrational numbers (Pi, e, sqrt(2), etc.) that
>> probabilistically the chance of not finding a given finite sequence of
>> digits goes to zero?
>>
>>
>> Most would bet that this is indeed the case, but that is unsolved today.
>>
>>
>>
>> Is it correct to say that almost surely
>>  any sequence can be found?
>>
>>
>> Hmm… “almost” has already a technical meaning in computer science. It
>> means for all but a finite number exceptions. It  existential dual is
>> “there is infinitely many …”.
>>
>> Then, I don’t want to look like pick nicking, but “almost” and “sure”
>> seems a bit antinomic.
>>
>> Some intuition of infinite decimal series, and of irrational numbers
>> (which have no infinite repetition, etc.) gives a feeling that it would be
>> quite astonishing that it is not the case, even for sqrt(2), and we can say
>> that this has been experimentally verified, but mathematicians ask for
>> proof, and some ask for an elementary proof (not involving second order
>> arithmetic or analysis).
>>
>>
>>
>>
>> If it does not hold for Pi, are there other numbers that would be better
>> examples for the type of analogy I am making?
>>
>>
>>
>> The Champernowne Number
>>
>> https://mathworld.wolfram.com/ChampernowneConstant.html
>>
>>
>>
>>
>> I want to show why statistically an infinite space leads to near
>> certainty of repetitions of material arrangements assuming some kind of
>> infinite uniformity, just like the infinity of random-looking digits of an
>> irrational number leads to infinite repetitions among any finite sequence.
>>
>>
>>
>> You get this with Champernowne number. It is normal, despite
>> extraordinarily compressible.  It is about equal to 0.123.., but all kids
>> can easily write the decimals without ending!  It is obviously normal, as
>> it goes through all the numbers, and thus all the sequences.
>>
>
> But the universe appears more random than something so well structured
> like the Champernowne constant.
>
>
>
> I doubt this. Most subsequence of the Champernowne number are completely
> random, and *very* long. Only the tiny initial segment does not look
> random, when you know the algorithm to generate it. It can be proved that
> most natural number have incompressible sequences. The number of compressed
> algorithm grows much less that the numbers of number (for each finite
> length).
>

I think like Pi, reality itself could be generated by a short compressible
algorithm (like the UD).

But also like Pi, if you find yourself at some arbitrary offset, it looks
like it is irreducibly random (like the quantum fluctuations that appear in
the distribution of galaxies and CMB of our universe).

Perhaps there is some law where when you combine a deterministic process
with infinite steps, the result is random. I have some familiarity with the
design of secure random number generates computers use to generate
encryption keys and other values that are necessary for security. All are
based on the process of taking a very large number (so large it can't be
guessed) then combining it with a deterministic, but difficult-to-reverse
(one-way) function.

The simplest example I cold easily describe is the one built into Java
called SHA1PRNG. It starts with a random number (a seed value) that is on
the order of 256 bits. Then to generate a sequence of random looking bits,
it puts this random number through a one-way hash function (called SHA1).
The output of this function only produces 160 random bits. If more are
needed the random seed value is incremented by 1, and 

Re: The size of the universe

[Bruno Marchal]

> On 21 May 2020, at 21:43, Jason Resch  wrote:
> 
> 
> 
> On Thu, May 21, 2020 at 1:33 PM Bruno Marchal  > wrote:
> 
>> On 20 May 2020, at 18:45, Jason Resch > > wrote:
>> 
>> 
>> 
>> On Wed, May 20, 2020 at 7:05 AM Bruno Marchal > > wrote:
>> 
>>> On 19 May 2020, at 05:20, Jason Resch >> > wrote:
>>> 
>>> I recently wrote an article on the size of the universe and the scope of 
>>> reality:
>>> https://alwaysasking.com/how-big-is-the-universe/ 
>>> 
>>> 
>>> It's first of what I hope will be a series of articles which are largely 
>>> inspired by some of the conversations I've enjoyed here. It covers many 
>>> topics including the historic discoveries, the big bang, inflation, string 
>>> theory, and mathematical realism.
>> 
>> 
>> 
>> It has not been proved that the decimal expansion of PI contains all (finite 
>> codes of all) sequences.
>> 
>> I understand that Pi is proven to be normal,
> 
> 
> (Oops I meant to say "Pi is not proven to be normal" somehow I deleted the 
> not while refactoring the sentence)

OK. 



>  
> 
> But that is not the case. Pi win all experimental test, but the normality of 
> basically all irrational numbers are open problems. It is generally 
> conjectured that they are all normal.
> For the Champernow number, the normality is easy to prove, but it has been 
> build that way.
> 
> 
> 
>> but is it true for the irrational numbers (Pi, e, sqrt(2), etc.) that 
>> probabilistically the chance of not finding a given finite sequence of 
>> digits goes to zero?
> 
> Most would bet that this is indeed the case, but that is unsolved today.
> 
> 
> 
>> Is it correct to say that almost surely 
>>  any sequence can be found?
> 
> Hmm… “almost” has already a technical meaning in computer science. It means 
> for all but a finite number exceptions. It  existential dual is “there is 
> infinitely many …”.
> 
> Then, I don’t want to look like pick nicking, but “almost” and “sure” seems a 
> bit antinomic. 
> 
> Some intuition of infinite decimal series, and of irrational numbers (which 
> have no infinite repetition, etc.) gives a feeling that it would be quite 
> astonishing that it is not the case, even for sqrt(2), and we can say that 
> this has been experimentally verified, but mathematicians ask for proof, and 
> some ask for an elementary proof (not involving second order arithmetic or 
> analysis).
> 
> 
> 
> 
>> If it does not hold for Pi, are there other numbers that would be better 
>> examples for the type of analogy I am making?
> 
> 
> The Champernowne Number
> 
> https://mathworld.wolfram.com/ChampernowneConstant.html 
> 
> 
> 
> 
> 
>> I want to show why statistically an infinite space leads to near certainty 
>> of repetitions of material arrangements assuming some kind of infinite 
>> uniformity, just like the infinity of random-looking digits of an irrational 
>> number leads to infinite repetitions among any finite sequence.
> 
> 
> You get this with Champernowne number. It is normal, despite extraordinarily 
> compressible.  It is about equal to 0.123.., but all kids can easily write 
> the decimals without ending!  It is obviously normal, as it goes through all 
> the numbers, and thus all the sequences. 
> 
> But the universe appears more random than something so well structured like 
> the Champernowne constant.


I doubt this. Most subsequence of the Champernowne number are completely 
random, and *very* long. Only the tiny initial segment does not look random, 
when you know the algorithm to generate it. It can be proved that most natural 
number have incompressible sequences. The number of compressed algorithm grows 
much less that the numbers of number (for each finite length). 



> What about Chaitin's Omega? Hasn't Chaitin proved a certain randomness for 
> that digits of that constant?


Up to see constant related to the universal machine used to make that number 
precise, it can be shown that indeed, that number (Omega) is random and 
incompressible. But all the finite subsequences of Omega appears in the 
Champernowne number, and only for that last one have we a proof of normality. 
Omega is so compressed that it has no useful pattern in it. 

Much more interesting is the Post number, which is 0,000110010101001… with 
1 (res 0) at the nth place if phi_n converges (or not), where phi_i is an 
enumeration of the programs without arguments.

Post number is compressible (indeed Chaitin’s Omega is Post number when 
maximally compressed: both gives the halting oracle). But post number 
illustrates the needed redundancy that we need to get the pattern from which 
the physical laws can evolve. It is an “interesting” number (in the sense of 
Bennett).




>  
> 
> It has not be confused with a 

Summer weather and COVID-19

[John Clark]

A new study from Harvard indicates that warmer weather and more humidity
and UV exposure will only modestly slow down the spread of the virus. It
all depends on the R value, the average number of people a infected person
will pass on the disease to others, if it's less than 1 the virus will
eventually die out. In Wuhan in the very early days of the epidemic before
any social distancing took effect R was found to be about 3.5. And this new
study suggests that the summer weather will likely reduce R by 43%,  and
that means R would still be way larger than 1. So that does not bode well
for the recent rash of reopenings that have been urged by some politicians,
by late summer or early fall we should know if this grim prediction was
correct.

Warmer weather alone will NOT be enough to fully contain the transmission
of COVID-19


John K Clark

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Models as Code (Differentiable Programming)

[Philip Thrift]

Models as Code: Differentiable Programming with Zygote (Julia programming 
language)

video: https://www.youtube.com/watch?v=Sv3d0k7wWHk

slides: 
https://www.microsoft.com/en-us/research/uploads/prod/2019/06/Models-as-Code-Differentiable-Programming-with-Zygote-slides.pdf

Zygote:
https://fluxml.ai/Zygote.jl/latest/
https://wookay.github.io/docs/Owl.jl/Zygote/

"Zygote extends the Julia language to support differentiable programming."

arXiv: https://arxiv.org/abs/1907.07587


@philipthrift

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Re: Universe as a simulated strange loop

[Bruno Marchal]

> On 20 May 2020, at 23:24, 'Brent Meeker' via Everything List 
>  wrote:
> 
> 
> 
> On 5/20/2020 5:24 AM, Bruno Marchal wrote:
>> 
>>> On 18 May 2020, at 21:35, 'Brent Meeker' via Everything List 
>>> >> > wrote:
>>> 
>>> 
>>> 
>>> On 5/18/2020 3:03 AM, Bruno Marchal wrote:
 
> On 18 May 2020, at 00:45, 'Brent Meeker' via Everything List 
>  > wrote:
> 
> 
> 
> On 5/17/2020 6:29 AM, Bruno Marchal wrote:
>> the appearance of matter as they are explained by the mechanist 
>> consciousness flux in arithmetic (itself explained by G and G* and their 
>> difference).
> 
> You frequently say this,
 
 Yes, it is the PhD content. 
 1) UDA = the constructive reduction of the mind-body problem to the 
 necessity of deriving he physical laws from arithmetic. 
 2) AUDA = the derivation itself.
 
> but I have not seen this explanation except in vague hand waving.
 
 Hand waving?
 
 Your remark does look like hand waving, I would say.
 
 Come on Brent, I am the guy who gives 8 precise mathematical theories, 
 three of them being concerned with the appearance of matter in arithmetic, 
 and so are testable, and indeed confirmed by all experiences until now.
>>> 
>>> They do not show the appearance of matter, the persistence of objects, the 
>>> shared reality.  You merely assume that they must...since otherwise your 
>>> theory doesn't work.
>> 
>> UDA explains that there is no other choice. It exposes the problem.
> 
> No, it simply asserts the problem follows from some axioms.

That is right, but the problem is solved constructively, so we can test the 
solution. And indeed, thanks to QM-without-collapse, we can say that Mechanism 
is vindicated by Nature.

Also, the axioms belongs to all theories rich enough to be Turing universal, 
which is already the case for the ultra-finitist presentation of arithmetic. 
(Nelson’s ultrafinitism starts from Robinson Arithmetic).

The physicalist solution seems to be obliged to put the first person, qualia, 
consciousness, under the rug, as it just cannot work without postulating a 
non-mechanist theory of mind, which still do not exist, unless speculation that 
gravity is consciousness and responsible for some wave packet reduction 
(Penrose).

Once you grasp that all computations are realised when we accept simple truth 
like the existence or inexsitence  of the solution of polynomial Diophantine 
equations, there is no more experimental evidence that a physical universe 
exists in any ontological sense, and doubly so, when the many-worlds aspect of 
nature confirms so well the many computations which provably are realised in a 
very tiny part of the arithmetical reality. 

The physicalist can still be right, so let us pursue the testing.That’s all. To 
make an ontological commitment at the start, is just non serious theology.

Bruno



> 
> Brent
> 
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>  
> .

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"magic" (in programming)

[Philip Thrift]

The term "magic" implies that the hidden complexity is at least in 
principle understandable, in contrast to black magic and deep magic (see 
Variants ), 
which describe arcane techniques that are deliberately hidden or extremely 
difficult to understand. 


https://en.wikipedia.org/wiki/Magic_(programming)

@philipthrift

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