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Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott <polcott333@gmail.com> Newsgroups: comp.theory Subject: =?UTF-8?Q?Re=3A_Definition_of_real_number_=E2=84=9D_--infinitesimal?= =?UTF-8?Q?--?= Date: Sun, 31 Mar 2024 14:42:59 -0500 Organization: A noiseless patient Spider Lines: 124 Message-ID: <uucec3$1vh78$1@dont-email.me> References: <bebe16f4f02eed7ac4e4d815dc0e1e98f9f0f2a0.camel@gmail.com> <uu3qk7$3jc94$1@dont-email.me> <uu444a$3lnuc$1@dont-email.me> <uu44k2$3lrph$1@dont-email.me> <uu50n4$3ca7i$6@i2pn2.org> <uu573n$3tt5t$7@dont-email.me> <uu58nh$3ca7j$2@i2pn2.org> <uu59t9$3ubje$2@dont-email.me> <8734s9u2tl.fsf@nosuchdomain.example.com> <uu5dqp$2tti$2@dont-email.me> <uu6ep9$3dq4u$4@i2pn2.org> <uu6npg$ceq1$1@dont-email.me> <uu79db$gdqk$1@dont-email.me> <875xx4sh0h.fsf@nosuchdomain.example.com> <uu7osb$k31e$1@dont-email.me> <87sf08qzt5.fsf@nosuchdomain.example.com> <uu7q21$k72e$1@dont-email.me> <uu8vf8$vsq2$1@dont-email.me> <uu95mr$114hv$5@dont-email.me> <uu9q43$16c9d$2@dont-email.me> <uu9qqn$16gt9$1@dont-email.me> <uu9s39$16gks$1@dont-email.me> <uu9sj2$16rdo$1@dont-email.me> <uucbe9$1utsv$2@dont-email.me> <uucc0e$1v1p5$1@dont-email.me> <uucdd7$1v8hd$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 31 Mar 2024 19:42:59 +0200 (CEST) Injection-Info: dont-email.me; posting-host="d274a2519002cc1ac6fed3e3c2f777ec"; logging-data="2082024"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+fFwcPKXqR8Mo7CNeXY84B" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:0lUcSleW39+lcyUTgEfKzvyZ7Dg= Content-Language: en-US In-Reply-To: <uucdd7$1v8hd$1@dont-email.me> Bytes: 7576 On 3/31/2024 2:26 PM, Fred. Zwarts wrote: > Op 31.mrt.2024 om 21:02 schreef olcott: >> On 3/31/2024 1:52 PM, Fred. Zwarts wrote: >>> Op 30.mrt.2024 om 21:27 schreef olcott: >>>> On 3/30/2024 3:18 PM, Fred. Zwarts wrote: >>>>> Op 30.mrt.2024 om 20:57 schreef olcott: >>>>>> On 3/30/2024 2:45 PM, Fred. Zwarts wrote: >>>>>>> Op 30.mrt.2024 om 14:56 schreef olcott: >>>>>>>> On 3/30/2024 7:10 AM, Fred. Zwarts wrote: >>>>>>>>> Op 30.mrt.2024 om 02:31 schreef olcott: >>>>>>>>>> On 3/29/2024 8:21 PM, Keith Thompson wrote: >>>>>>>>>>> olcott <polcott2@gmail.com> writes: >>>>>>>>>>>> On 3/29/2024 7:25 PM, Keith Thompson wrote: >>>>>>>>>>> [...] >>>>>>>>>>>>> What he either doesn't understand, or pretends not to >>>>>>>>>>>>> understand, is >>>>>>>>>>>>> that the notation "0.999..." does not refer either to any >>>>>>>>>>>>> element of >>>>>>>>>>>>> that sequence or to the entire sequence. It refers to the >>>>>>>>>>>>> *limit* of >>>>>>>>>>>>> the sequence. The limit of the sequence happens not to be >>>>>>>>>>>>> an element of >>>>>>>>>>>>> the sequence, and it's exactly equal to 1.0. >>>>>>>>>>>>> >>>>>>>>>>>> In other words when one gets to the end of a never ending >>>>>>>>>>>> sequence >>>>>>>>>>>> (a contradiction) thenn (then and only then) they reach 1.0. >>>>>>>>>>> >>>>>>>>>>> No. >>>>>>>>>>> >>>>>>>>>>> You either don't understand, or are pretending not to >>>>>>>>>>> understand, what >>>>>>>>>>> the limit of sequence is. I'm not offering to explain it to >>>>>>>>>>> you. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> I know (or at least knew) what limits are from my college >>>>>>>>>> calculus 40 >>>>>>>>>> years ago. If anyone or anything in any way says that 0.999... >>>>>>>>>> equals >>>>>>>>>> 1.0 then they <are> saying what happens at the end of a never >>>>>>>>>> ending >>>>>>>>>> sequence and this is a contradiction. >>>>>>>>>> >>>>>>>>> >>>>>>>>> It is clear that olcott does not understand limits, because he >>>>>>>>> is changing the meaning of the words and the symbols. Limits >>>>>>>>> are not talking about what happens at the end of a sequence. It >>>>>>>>> seems it has to be spelled out for him, otherwise he will not >>>>>>>>> understand. >>>>>>>>> >>>>>>>> >>>>>>>> 0.999... Limits basically pretend that we reach the end of this >>>>>>>> infinite sequence even though that it impossible, and says after >>>>>>>> we reach this >>>>>>>> impossible end the value would be 1.0. >>>>>>> >>>>>>> No, if olcott had paid attention to the text below, or the >>>>>>> article I referenced: >>>>>>>> https://en.wikipedia.org/wiki/Construction_of_the_real_numbers >>>>>>> >>>>>>> he would have noted that limits do not pretend to reach the end. >>>>>>> They >>>>>> >>>>>> Other people were saying that math says 0.999... = 1.0 >>>>> >>>>> Indeed and they were right. Olcott's problem seems to be that he >>>>> thinks that he has to go to the end to prove it, but that is not >>>>> needed. We only have to go as far as needed for any given ε. Going >>>>> to the end is his problem, not that of math in the real number system. >>>>> 0.999... = 1.0 means that with this sequence we can come as close >>>>> to 1.0 as needed. >>>> >>>> That is not what the "=" sign means. It means exactly the same as. >>> >>> No, olcott is trying to change the meaning of the symbol '='. That >>> *is* what the '=' means for real numbers, because 'exactly the same' >>> is too vague. Is 1.0 exactly the same as 1/1? It contains different >>> symbols, so why should they be exactly the same? >> >> It never means approximately the same value. >> It always means exactly the same value. > > And what 'exactly the same value' means is explained below. It is a > definition, not an opinion. > No matter what you explain below nothing that anyone can possibly say can possibly show that 0.000... = 1.0 I use categorically exhaustive reasoning thus eliminating the possibility of correct rebuttals. >> >>> Therefore, in the construction of reals it is defined how to >>> determine whether two reals are 'exactly' the same. If one real X can >>> be constructed with a sequence of xn and the other real Y with a >>> sequence yn, then we can use X = Y if for every rational ε > 0 we can >>> find an N so that for all n > N |xn - yn| < ε. >>> The consequence of this is that for each real we can use an infinite >>> number of Cauchy sequences. E.g. the following sequences >>> a: 1/1, 1/1, 1/1, 1/1, etc. >>> b: 9/10, 99/100, 999/1000, etc. >>> c: 10/9, 100/99, 1000/999, etc. >>> d: 1/2, 2/3, 3/4, 4/5, etc. >>> e: 1/2, 3/2, 3/4, 5/4, 5/6, 7/6, etc. >>> are all sequences that are different representations of the same real >>> which in decimal notation can be written as 1. So, a=b=c=d=e=1. >>> Olcott may not like it, but that is how the '=' is defined for reals. >>> One may try to create another number system with another meaning for >>> '=', but then we are not talking about reals any more. >>> If I do not like that 3+4=7, then I can try to create another system >>> for which 3+4=6 holds, which I like more, but I am no longer speaking >>> of real numbers (and probably nobody is interested in my number system). > > For real numbers, a has exactly the same value as b, c, d, e, f and 1. > That is how it is defined. If olcott has another definition of 'exactly > the same value', then he is changing the meaning of the words. The > meaning of '=' is exactly defined for reals. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer