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Author Topic:   0.99999~ = 1 ?
Dr Jack
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Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.3


Message 31 of 237 (543220)
01-16-2010 10:06 AM
Reply to: Message 30 by cavediver
01-16-2010 9:42 AM


Re: 1 and NOT 1
Yeah, but finitism is silly.

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cavediver
Member (Idle past 3673 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 32 of 237 (543222)
01-16-2010 10:14 AM
Reply to: Message 31 by Dr Jack
01-16-2010 10:06 AM


Re: 1 and NOT 1
Yeah, but finitism is silly.
I'll not disagree
Edited by cavediver, : No reason given.

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cavediver
Member (Idle past 3673 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 33 of 237 (543223)
01-16-2010 10:22 AM
Reply to: Message 28 by Huntard
01-16-2010 8:17 AM


Re: Funny Properties
Ah yes. Even if every digit were the size of only 1 planck volume, the observable universe would still not be big enough to contain a digital representation of it
It's far worse than that! Let's say that for each Planck volume, you are given another entire universe!! And for each Planck volume in that universe, you are given *another* universe!! You would still not have enough Planck volumes to even begin to write out Graham's number

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Dr Adequate
Member (Idle past 314 days)
Posts: 16113
Joined: 07-20-2006


Message 34 of 237 (543226)
01-16-2010 11:27 AM
Reply to: Message 13 by PaulK
01-15-2010 5:51 PM


Re: Hmm, equal?
That is, two numbers a and b are equal if there is no number, e such that
|a - b| < e
Read through that again.
You meant to say "if for every (positive) number e, |a - b| < e".
Or possibly you meant to say "if there is no (positive) number e such that |a - b| > e".
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 314 days)
Posts: 16113
Joined: 07-20-2006


Message 35 of 237 (543228)
01-16-2010 12:04 PM
Reply to: Message 16 by Straggler
01-15-2010 7:26 PM


Re: 1 and NOT 1
Surely the difference between 0.999R and 1 is practically non-existant and philosophically massive?
It is the difference between claiming complete certainty (for example) and always allowing for the possibility of that which is unexpected (no matter how likely or unlikely). It is the difference between an obtainable destination and that which can never exist or be obtained in reality.
I am no mathematician. But surely the difference between 1 and NOT 1 is as significant as ever. No matter what the NOT 1 may be?
It's funny, no-one has any difficulty with grasping that 1/2 and 2/4 are the same thing.
Well, here we have a similar situation. We happen to use a system of notation in which sometimes there is more than one way to write exactly the same number.
Edited by Dr Adequate, : No reason given.

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Son Goku
Inactive Member


Message 36 of 237 (543229)
01-16-2010 12:15 PM
Reply to: Message 25 by cavediver
01-16-2010 5:20 AM


Re: Funny Properties
Ah, Graham's number isn't that big, it's less than Graham's number + 1. In fact most numbers are probably bigger than it.

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Son Goku
Inactive Member


Message 37 of 237 (543230)
01-16-2010 12:27 PM
Reply to: Message 26 by cavediver
01-16-2010 5:28 AM


Constructivism
This whole Constructivist thing confuses me, I hope you can help.
Surely constructivism assumes a somewhat Platonist view. If you are being a total formalist then the rules/axioms of infinite series are consistent and that's all it means for 0.999.... to exist. That is, it is a game of symbols and rules which doesn't contradict itself. In order to say 0.9999.... doesn't exist, you need to think there was an objective mathematical reality and only constructive methods get you there.
If you know, what do constructivists think of standard math? Do they believe what is constructive is Platonically true and anything else is just formalist games with pen and paper?
Usually I would be skeptical about such a philosophy, however Edward Nelson is a constructivist and he's no fool. (He took the first real hard steps toward showing Quantum Field Theory makes sense mathematically.)

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Straggler
Member (Idle past 95 days)
Posts: 10333
From: London England
Joined: 09-30-2006


Message 38 of 237 (543355)
01-17-2010 3:20 PM
Reply to: Message 35 by Dr Adequate
01-16-2010 12:04 PM


Re: 1 and NOT 1
Well It appears that the genaral consensus amongst those who are more mathematically literate than myself is that I am wrong.
In which case I stand corrected. And in which case I will need to find a new nomenclature for expressing all but certain without the philosophical possibility of complete and absolute certainty.
But just to be clear is it false to say that 0.999R < 1?

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Straggler
Member (Idle past 95 days)
Posts: 10333
From: London England
Joined: 09-30-2006


Message 39 of 237 (543357)
01-17-2010 3:22 PM
Reply to: Message 23 by Huntard
01-16-2010 4:08 AM


Re: 1 and NOT 1
This is a genuine question. As it appears that my understanding up until now has been incomplete (to put it politely - or just wrong if we are to be more blunt.
But is it wrong to say that 0.999R <1?

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Straggler
Member (Idle past 95 days)
Posts: 10333
From: London England
Joined: 09-30-2006


Message 40 of 237 (543358)
01-17-2010 3:26 PM
Reply to: Message 27 by Dr Jack
01-16-2010 7:22 AM


1 and NOT 1 As Probability
Nope, they're completely the same, philosophically and otherwise.
Well up until now I have (rightly or wrongly) been expressing the difference between probablistic certainty or otherwise as the differnce between 1 and NOT 1. Where (in my mind at least) 0.999R is not equal to 1.
It appears I am need to change my nomenclature. But I am not sure what I should use instead?
Nope. There is no uncertainty, 0.9999~ is 1. In fact all decimal representations are infinite sequences, it's just some of them finish in an infinite number of 0s. This is not, as it may sound, a cute aphorism but actually fundamental to the construction of the real numbers. Real numbers are limits of inifnite sequences.
Well I get what you are saying. I think. But it still seems counter-intuitive that 1/0.999R is entirely equal to 1/1. For example.

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PaulK
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Posts: 17828
Joined: 01-10-2003
Member Rating: 2.3


Message 41 of 237 (543361)
01-17-2010 3:35 PM
Reply to: Message 39 by Straggler
01-17-2010 3:22 PM


Re: 1 and NOT 1
quote:
But is it wrong to say that 0.999R <1?
I'm afraid that it is. Unless you can show that 1 - 0.999R is greater than zero.
(Hint: What is the decimal expansion of 1 - 0.999R. How far do you have to go to find a non-zero digit ?)

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Straggler
Member (Idle past 95 days)
Posts: 10333
From: London England
Joined: 09-30-2006


Message 42 of 237 (543365)
01-17-2010 3:50 PM
Reply to: Message 41 by PaulK
01-17-2010 3:35 PM


Re: 1 and NOT 1
Double post. See below.
Edited by Straggler, : No reason given.

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Straggler
Member (Idle past 95 days)
Posts: 10333
From: London England
Joined: 09-30-2006


Message 43 of 237 (543366)
01-17-2010 3:51 PM
Reply to: Message 41 by PaulK
01-17-2010 3:35 PM


Re: 1 and NOT 1
I'm afraid that it is.
Yeah I am starting to get that despite inbuilt resistance.
Unless you can show that 1 - 0.999R is greater than zero.
Can it be shown mathematically that 1 - 0.999R is equal to zero?
(Hint: What is the decimal expansion of 1 - 0.999R. How far do you have to go to find a non-zero digit ?)
One step further down the infinite chain than you need to go to make 0.999R the same as 1?

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Huntard
Member (Idle past 2324 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 44 of 237 (543369)
01-17-2010 3:56 PM
Reply to: Message 43 by Straggler
01-17-2010 3:51 PM


Re: 1 and NOT 1
Straggler writes:
Can it be shown mathematically that 1 - 0.999R is equal to zero?
Yes, since they are the same.
One step further down the infinite chain than you need to go to make 0.999R the same as 1?
How many steps does an infinte chain contain then? And what is infinity + 1?

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I am the one Orgasmatron, the outstretched grasping hand
My image is of agony, my servants rape the land
Obsequious and arrogant, clandestine and vain
Two thousand years of misery, of torture in my name
Hypocrisy made paramount, paranoia the law
My name is called religion, sadistic, sacred whore.
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PaulK
Member
Posts: 17828
Joined: 01-10-2003
Member Rating: 2.3


Message 45 of 237 (543373)
01-17-2010 4:02 PM
Reply to: Message 43 by Straggler
01-17-2010 3:51 PM


Re: 1 and NOT 1
quote:
Can it be shown mathematically that 1 - 0.999R is equal to zero?
Yes we can show that there is no number between it and zero, for instance (you can get that from the fact that there is no number between 1 and 0.999R)
quote:
One step further down the infinite chain than you need to go to make 0.999R the same as 1?
Nice attempt to turn it around. However, would you agree that 1 - 0.999R is zero to an infinite precision ?

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