Sujet : Re: Simple enough for every reader?
De : wolfgang.mueckenheim (at) *nospam* tha.de (WM)
Groupes : sci.logicDate : 02. Jul 2025, 14:51:01
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <1043dg5$3hor7$1@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
User-Agent : Mozilla Thunderbird
On 02.07.2025 09:45, Mikko wrote:
On 2025-06-30 18:21:09 +0000, WM said:
On 29.06.2025 12:25, Mikko wrote:
That is potential infinity. But Cantor claimed complete enumeration.
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There is no mathematical definiton of "complete enumeration"
Obviously you don't know much of mathematics.
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The definition of bijection requires completeness.
No, it doesn't.
The function is injective, or one-to-one, if each element of the codomain is mapped to by at most one element of the domain,
The function is surjective, or onto, if each element of the codomain is mapped to by at least one element of the domain; Wikipedia
Bijection = injection and surjection.
Note that no element must be missing. That means completeness.
However, that doesn't really matter as the distinction between complete
and incomplete is not mathematical.
Obviously you don't know the most important parts of mathematics.
"Cantor's belief in the actual existence of the infinite of Set Theory still predominates in the mathematical world today." [A. Robinson: "The metaphysics of the calculus", in I. Lakatos (ed.): "Problems in the philosophy of mathematics", North Holland, Amsterdam (1967) p. 39]
Note belief and predominate.
"The arguments using infinity, including the Differential Calculus of Newton and Leibniz, do not require the use of infinite sets." [T. Jech: "Set theory", Stanford Encyclopedia of Philosophy (2002)]
"Should we briefly characterize the new view of the infinite introduced by Cantor, we could certainly say: In analysis we have to deal only with the infinitely small and the infinitely large as a limit-notion, as something becoming, emerging, produced, i.e., as we put it, with the potential infinite. But this is not the proper infinite. That we have for instance when we consider the entirety of the numbers 1, 2, 3, 4, ... itself as a completed unit, or the points of a line as an entirety of things which is completely available. That sort of infinity is named actual infinite." [D. Hilbert: "Über das Unendliche", Mathematische Annalen 95 (1925) p. 167]
It means that no further element can be found later on.
Whether an element is "found" has no mathematical meaning and in particular
does not affect its being or not a member of some set.
"Numerals constitute a potential infinity. Given any numeral, we can construct a new numeral by prefixing it with S." [E. Nelson: "Hilbert's mistake" (2007) p. 3]
Then it cannot be. If it is that all natural numbers are subtracted in their order, then it is that a last one is subtracted.
Given two sets there is a set that is their difference. There is no
opeartion of subtraction in order.
The set ℕ has an intrinsic order which can be used at any time. Bijecting sets presupposes and requires order. Further the difference of sets depends strongly on the order assumed.
You are wrong. Here are only few pages of my Book Transfinity:
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4.1 Cantor on theology
Theology is not mathematics.
Set theory is theology. You are right, set theory is not mathematics.
Regards, WM