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From: Virgil on 2 Dec 2009 15:47 In article <a7ae8268-3626-4a9f-9902-65662d39d7a3(a)m25g2000yqc.googlegroups.com>, WM <mueckenh(a)rz.fh-augsburg.de> wrote: > On 2 Dez., 14:14, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > > In article > > <12b419b5-1a9f-42c1-b9bc-0e8a2cce2...(a)z41g2000yqz.googlegroups.com> WM > > <mueck...(a)rz.fh-augsburg.de> writes: > > �> On 1 Dez., 14:57, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > > ... > > �> > �> You may write this as often as you like, but you are wrong. If > > there > > �> > �> is a limit set then there is a limit cardinality, namely the number > > of > > �> > �> elements in that limit set. Everything else is nonsense. > > �> > > > �> > Can you prove the assertion that the limit of the cardinalities is the > > �> > cardinality of the limit? > > �> > > �> With pleasure. My assertion is obvious if the limit set actually > > �> exists. > > > > No it is not. > > > > �> Limit cardinality = Cardinality of the limit-set. > > > > You are conflating within limit cardinality the limit of the cardinalities > > and the cardinality of the limit. �You have to prove they are equal. > > If the limit set exists, then it has a cardinal number, hasn't it? > > > > �> If it does not exist, set theory claiming the existence of actual > > �> infinity is wrong. > > > > Both can exist but they are not necessarily equal, you have to *prove* > > that. > > If a set exists (and if ZFC is correct), then that set has a > cardinality. If the limit set exists, then it has a cardinality. I > call that the cardinality of the limit set, abbreviated by limit > cardinality. If the limit of cardinalities differs, then either the > calculation is wrong or the theory whereupon the calculation is based. To demonstrate that the cardinality of a limit process of a seqeunce of non-cardinals equals a different sort of limit process of a sequence of cardinals requires more proof that WM is capable of producing. > It is so simple. WM is what is 'simple' here. Too simple to see that something is beyond his ken. > There is as little proof required as in necessary to > show that you are Dik T. Winter. If there is any theory showing that > you are not DTW or that you are 20 meters tall, then that theory is > simply wrong - without further proof. > > > > �> > �I can prove that it can be false. �As I wrote, > > �> > given: > > �> > � �S_n = {n, n+1} > > �> > we have (by the definition of limit of sets: > > �> > � �lim{n -> oo} S_n = {} > > �> > > �> This is wrong. > > > > You have never looked at the definition I think. �Given a sequence of sets > > S_n then: > > � �lim sup{n -> oo} S_n contains those elements that occur in infinitely > > � � � � � � � � � � many S_n > > � �lim inf{n -> oo} S_n contains those elements that occur in all S_n from > > � � � � � � � � � � a certain S_n (which can be different for each > > element). > > � �lim{n -> oo} S_n exists whenever lim sup and lim inf are equal. > > With this definition lim{n -> oo} S_n exists and is equal to {}. > > Then the theory is wrong. Definitions cannot be 'wrong'. They can be useless, but not wrong. > If another set exists and the calculation of > its cardinality gives not the cardinality of that set, what would you > conclude? That the two sets are distinct. > > Well, in set the theory the limit set is claimed to exist. Not always. According to the definition above, there is a necessary condition for that limit, which need not always be met, in which case the limit does NOT exist. Thus one may imagine a situation in which the limit of the cardinalities does exist but the limit of the sequence of sets does not exist. e.g., a sequence of sets all of the same cardinality but for which neither lim sup nor lim inf exist. > > > > �> � � � � � ong. You may find it helpful to see the approach where I > > �> show a related example to my students. > > �> > > �>http://www.hs-augsburg.de/~mueckenh/GU/GU12.PPT#394,22,Folie22 > > > > I see nothing related there. �It just shows (I think) an open cube and a > > cylinder. > > You must move on. There is always a number remaining in the cylinder > (the example stretches only until 6, but you should imagine how it > continues). > > It shows: If you union all natural numbers within the cube, then it is > said that you get all natural numbers, the complete set N. But if you > union all natural numbers such that each one makes an intermediate > stop in the cylinder and does not move on before the next one, n+1, > has dropped in, then you cannot union all natural numbers within the > cube. This simple example shows, that it is impossible to union all > natural numbers at all. Students easily understand, that this union is > but a silly idea of unmathematical people. Unfortunately for WM, the very people whom he calls unmathemtical are the very ones who create all the mathematics that he pretends to understand. > > > > > > �> > and so > > �> > � �2 = lim{n -> oo} | S(n) | != | lim{n -> oo} S_n | = 0 > > �> > or can you show what I wrote is wrong? > > �> > > �> Yes I can.* If actual infinity exists*, then the limit set exists. > > > > I have still no idea what the mathematical definition of "actual infinity" > > is, but given the definitions above, the limit of the sequence of sets > > exists and is the empty set. > > Actual infinity is completed infinity. And, by WM's definition, Completed infinity is actual infinity. Unfortunately, neither is relevant to set theory. > Unless actual infinity is assumed, no infinite counting comes to an > end. No diagonal number comes ever into being. Actual one-at-at-a-time counting may not end in situations in which bijections are known to exist. In which case one-at-a-time counting is irrelevant to 'counting' of the whole. > > > > �> Then the limit set has a cardinal number which can be determined > > �> simply by counting its elements. > > �> A simple example is > > �> | lim[n --> oo] {1} | = | {1} | = lim[n --> oo] |{1}| = 1. > > > > Right. �And as in the above example the limit is the empty set, we can > > count > > the elements and come at 0. > > This proves set theory wrong. It only proves WM wrong. In the vase (and in the cylinder in > http://www.hs-augsburg.de/~mueckenh/GU/GU12.PPT#394,22,Folie 22 > there is always at least one element. Hence cardinality is 1 in the > limit. That is like saying that the intersection of {1,2,3} and {4,5,6} has 3 elements in it because each set heas three elements in it. > > > > �> If you were right, that | lim[n --> oo] S_n | =/= lim[n --> oo] |S_n| > > �> was possible, then �the limit set would not actually exist (such that > > �> its elements could be counted and a different limit could be shown > > �> wrong). > > > > The limit set is empty. NO emptier that WM's head. > > The limit set is the same as in case 1, 1, 1, ... --> 1 > It is never empty and has never cardinality 0. > > > > �> > �If so, what line is wrong? > > �> > > �> Wrong is your definition of limit set, or set theory claiming actual > > �> infinity as substantially existing, or both. > > > > What is *your* definition of the limit of a sequence of sets? > > There is no actual infinity. WM only gets to command what happens when safe in Wolkenmuekenheim. Outside of his little private country WM no longer rules. > Hence there is no limit set. The only > thing you can do is this: You can look into my cylinder at any time > you like and you will find at least one element inside. One more than is in his head. > > Please note the difference: The limit of the *sequence* (1/n) is 0. > But there is no term 1/n = 0. The limit is not assumed by the > sequence. It is defined by means of epsilon. But it is not a limit of a sequence of sets nor of sequence of cardinalites, so it is doubly irrelevant. WM fails by imagining that all limits must behave identically even when they cannot behave identically. > > The limit of ({1, 2, 3, ...n}) however is assumed to exist as N (and > my cylinder being empty). Our discussion shows that this assumption is > untenable. WM's discussin may seem to show that, but his discussion is not valid outside Wolkenmuekenheim. > > Regards, WM
From: Virgil on 2 Dec 2009 18:44 In article <0c635f53-f5c4-4320-8825-de05f021a428(a)m3g2000yqf.googlegroups.com>, WM <mueckenh(a)rz.fh-augsburg.de> wrote: > On 2 Dez., 16:27, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > > > > > Limit cardinality is confusing because it can either mean the cardinality > > of the limit set or the limit of the cardinalities. > > If the limit set is "assumed" by the sequence of sets, if for instance > N is given by unioning all naturla numbers, then tghe limit set has to > have the limit cardinality. If both differ, then there is something > fishy about the theory. Not at all. There are all sorts of places in mathematics where two different operations fail to commute. It is indeed more common for them not to comute than of them to commute. So that the obligation is for WM to prove his claim. > > > > �> � � � � � � �If the limit of cardinalities differs, then either the > > �> calculation is wrong or the theory whereupon the calculation is based. > > > > Why? �I have given you a precise definition of the limit of a sequence of > > sets. �With that definition the limit of cardinalities is different from > > the cardinality of the limit, as is easily calculated. �So, what part of > > the theory is wrong? > > My argument is comparable to the following: > > If you want to prove that the determinant of a matrix M with not > ecclusively linear independent rows is det(M) = 0, you go two ways: > You multiply a row of the matrix M by 0, and you empty a row of M by > elementary operations which do not change the determinant. Then you > have proved that the original matrix M has the determinant 0. If you are allowed to multiply one row by zero, every square matrix would have determinant zero. > > Same holds for cardinals of sets. How do you muliply one row of a set by zero? Or take its determinant? > You form a set by unioning its > elements, resulting in the complete set. Only in Wolkenmuekenheim. In real set theories, unioning its elements, even if possible, does not produce the set. In some set theories the elements of a set need not all be sets so are incapable of being unioned at all. > This cannot change the > connection between cardinal number and set during the whole process of > formation. For every step the cardinal number and the number of > elements of the set are equal. Except the limit need not be one of the steps, even if what you are saying were relevant. > > The set N can be constructed by unioning all naturals. Or the set can > be taken from the shelf. Both ways must lead to the same result. How > could it be that the due cardinalities differ? Who says that we are talking about the set N? > > Same holds for the cylinder. Its contents is > {1}, {1}, {1}, {1} , ... > and that is not different from > {1}, {2}, {3}, {4} , ... > as you can see by renaming the elements. No number of specific examples prove a general rule to be valid unless one includes EVERY specific case in these specific examples. Which WM has not done. > > Regards, WM > > I think that this answers all the questions contained in the > following. Therefore I extinguish it. The only thing 'in the following' was WM's claim: "Therefore I extinguish it."
From: Dik T. Winter on 3 Dec 2009 07:52 In article <0c635f53-f5c4-4320-8825-de05f021a428(a)m3g2000yqf.googlegroups.com> WM <mueckenh(a)rz.fh-augsburg.de> writes: > On 2 Dez., 16:27, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > > Limit cardinality is confusing because it can either mean the cardinality > > of the limit set or the limit of the cardinalities. > > If the limit set is "assumed" by the sequence of sets, if for instance > N is given by unioning all naturla numbers, then tghe limit set has to > have the limit cardinality. The limit set is not necessarily "assumed" by the sequence of sets (if by that you mean that there is a set in the sequence that is equal to the limit set, if you mean something else I do not understand it at all). When you mean with your statement about N: N = union{n is natural} {n} then that is not a limit. Check the definitions about it. So what you wrote is complete nonsense. > If both differ, then there is something > fishy about the theory. There is something fishy about how you think things work in mathematics. > > > If the limit of cardinalities differs, then either the > > > calculation is wrong or the theory whereupon the calculation is based. > > > > Why? I have given you a precise definition of the limit of a sequence of > > sets. With that definition the limit of cardinalities is different from > > the cardinality of the limit, as is easily calculated. So, what part of > > the theory is wrong? > > My argument is comparable to the following: So below is your argument: > If you want to prove that the determinant of a matrix M with not > ecclusively linear independent rows is det(M) = 0, you go two ways: > You multiply a row of the matrix M by 0, and you empty a row of M by > elementary operations which do not change the determinant. Then you > have proved that the original matrix M has the determinant 0. So you argue that each matrix has determinant 0? If not what do you mean with that? > Same holds for cardinals of sets. You form a set by unioning its > elements, resulting in the complete set. You can not unite the elements if the elements are not sets in themselves and when the elements are sets, the union of the elements is different from the original set. Consider: A = {{a, b}, {b, c}, {c, d}} uniting the elements gives: B = {a, b, c, d} quite different. > This cannot change the > connection between cardinal number and set during the whole process of > formation. For every step the cardinal number and the number of > elements of the set are equal. What do you mean with "every step"? Uniting sets is a single step operation. > Same holds for the cylinder. Its contents is > {1}, {1}, {1}, {1} , ... > and that is not different from > {1}, {2}, {3}, {4} , ... > as you can see by renaming the elements. I do not understand this at all. > I think that this answers all the questions contained in the > following. Therefore I extinguish it. No. I asked you for a mathematical definition of "actual infinity" and you told me that it was "completed infinity". Next I asked you for a mathematical definition of "completed infinity" but you have not given an answer. So I still do not know what either "actual infinity" or "completed infinity" are. -- dik t. winter, cwi, science park 123, 1098 xg amsterdam, nederland, +31205924131 home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/
From: WM on 3 Dec 2009 09:46 On 3 Dez., 13:52, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > In article <0c635f53-f5c4-4320-8825-de05f021a...(a)m3g2000yqf.googlegroups.com> WM <mueck...(a)rz.fh-augsburg.de> writes: > > On 2 Dez., 16:27, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: > > > Limit cardinality is confusing because it can either mean the cardinality > > > of the limit set or the limit of the cardinalities. > > > > If the limit set is "assumed" by the sequence of sets, if for instance > > N is given by unioning all naturla numbers, then tghe limit set has to > > have the limit cardinality. > > The limit set is not necessarily "assumed" by the sequence of sets (if by > that you mean that there is a set in the sequence that is equal to the > limit set, if you mean something else I do not understand it at all). When > you mean with your statement about N: > N = union{n is natural} {n} > then that is not a limit. Check the definitions about it. It is a limit. That is independent from any definition. > > So below is your argument: > > > If you want to prove that the determinant of a matrix M with not > > ecclusively linear independent rows is det(M) = 0, you go two ways: > > You multiply a row of the matrix M by 0, and you empty a row of M by > > elementary operations which do not change the determinant. Then you > > have proved that the original matrix M has the determinant 0. > > So you argue that each matrix has determinant 0? If not what do you > mean with that? > > > Same holds for cardinals of sets. You form a set by unioning its > > elements, resulting in the complete set. > > You can not unite the elements if the elements are not sets in themselves > and when the elements are sets, the union of the elements is different > from the original set. Consider: > A = {{a, b}, {b, c}, {c, d}} > uniting the elements gives: > B = {a, b, c, d} > quite different. Not at all different with respect to being a limit process. > > > This cannot change the > > connection between cardinal number and set during the whole process of > > formation. For every step the cardinal number and the number of > > elements of the set are equal. > > What do you mean with "every step"? Uniting sets is a single step > operation. > No. Uniting two sets or singlets or elements is a single-step operation. Uniting infinitely many sets or singlets or elements is a limit process. > > Same holds for the cylinder. Its contents is > > {1}, {1}, {1}, {1} , ... > > and that is not different from > > {1}, {2}, {3}, {4} , ... > > as you can see by renaming the elements. > > I do not understand this at all. I see. You seem to share that fate with most so-called matematicians. > > > I think that this answers all the questions contained in the > > following. Therefore I extinguish it. > > No. I asked you for a mathematical definition of "actual infinity" and you > told me that it was "completed infinity". Next I asked you for a mathematical > definition of "completed infinity" but you have not given an answer. So I > still do not know what either "actual infinity" or "completed infinity" are. Both are nonsense. But both are asumed to make sense in set theory. The axiom of infinity is adefinition of actual infinity. "There *exists* a set such that ..." Without that axiom there is only potential infinity, namely Peano arithmetic. Regards, WM Regards, WM
From: Dik T. Winter on 3 Dec 2009 10:27
In article <27aee2d6-5966-4b62-a026-fea13e0bad6c(a)h2g2000vbd.googlegroups.com> WM <mueckenh(a)rz.fh-augsburg.de> writes: > On 3 Dez., 13:52, "Dik T. Winter" <Dik.Win...(a)cwi.nl> wrote: .... > > > If the limit set is "assumed" by the sequence of sets, if for instance > > > N is given by unioning all naturla numbers, then tghe limit set has to > > > have the limit cardinality. > > > > The limit set is not necessarily "assumed" by the sequence of sets (if by > > that you mean that there is a set in the sequence that is equal to the > > limit set, if you mean something else I do not understand it at all). > > When you mean with your statement about N: > > N = union{n is natural} {n} > > then that is not a limit. Check the definitions about it. > > It is a limit. That is independent from any definition. It is not a limit. Nowhere in the definition of that union a limit is used or mentioned. > > You can not unite the elements if the elements are not sets in themselves > > and when the elements are sets, the union of the elements is different > > from the original set. Consider: > > A = {{a, b}, {b, c}, {c, d}} > > uniting the elements gives: > > B = {a, b, c, d} > > quite different. > > Not at all different with respect to being a limit process. What limit process? Are there cases that A and B are equal? > > > This cannot change the > > > connection between cardinal number and set during the whole process of > > > formation. For every step the cardinal number and the number of > > > elements of the set are equal. > > > > What do you mean with "every step"? Uniting sets is a single step > > operation. > > No. Uniting two sets or singlets or elements is a single-step > operation. > Uniting infinitely many sets or singlets or elements is a limit > process. You are wrong. We have had this discussion before. Uniting a collection of sets is a single step process, regardless the number of sets involved (which number can be uncountable). Look up the definition of the union of a collection of sets in ZF. When you do not understand how some mathematics work, do not critisise it. > > > Same holds for the cylinder. Its contents is > > > {1}, {1}, {1}, {1} , ... > > > and that is not different from > > > {1}, {2}, {3}, {4} , ... > > > as you can see by renaming the elements. > > > > I do not understand this at all. > > I see. You seem to share that fate with most so-called matematicians. The only thing I see about that cylinder is that it contains some numbers, never changing. > > > I think that this answers all the questions contained in the > > > following. Therefore I extinguish it. > > > > No. I asked you for a mathematical definition of "actual infinity" and > > you told me that it was "completed infinity". Next I asked you for a > > mathematical definition of "completed infinity" but you have not given > > an answer. So I still do not know what either "actual infinity" or > > "completed infinity" are. > > Both are nonsense. But both are asumed to make sense in set theory. No, set theory does not contain a definition of either of them. > The axiom of infinity is adefinition of actual infinity. > "There *exists* a set such that ..." > Without that axiom there is only potential infinity, namely Peano > arithmetic. I see neither a definition of the words "actual infinity" neither a definition of "potential infinity". Or do you mean that "potential infinity" is Peano arithmetic (your words seem to imply that)? So we can say that in "potential infinity" consists of a set of axioms? -- dik t. winter, cwi, science park 123, 1098 xg amsterdam, nederland, +31205924131 home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/ |