Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: WM Newsgroups: sci.math Subject: Re: The set of necessary FISONs Date: Tue, 11 Feb 2025 20:23:28 +0100 Organization: A noiseless patient Spider Lines: 53 Message-ID: References: <1ab7ff67-f1fb-4814-9d28-c883a4756097@att.net> <451804be-c49f-43ab-bca9-8a4af406d945@att.net> <11e634bd-c1d3-4d72-9e18-be6ca22b4742@att.net> <999fb07e-7bef-4423-afeb-a08922613c65@att.net> <0d24c3fd-cd63-4e21-9dd4-ab1360560b09@att.net> <79920977-902d-4f59-a11c-497383221c82@att.net> <468b9c37-ba93-485c-8685-4b320e168251@att.net> <68bab5c2-50d3-43fc-be0d-51e01c5952bb@att.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 11 Feb 2025 20:23:30 +0100 (CET) Injection-Info: dont-email.me; posting-host="0f5dc8c5e62a53f43a491ce087496883"; logging-data="1965785"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/fkL6oj+m9TaO+MtuPhX2XZrTwb9OcFvk=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:X4s2Mpm+OycTIRQEixZF7WtZZvs= In-Reply-To: Content-Language: en-US Bytes: 3445 On 11.02.2025 18:42, Jim Burns wrote: > On 2/11/2025 4:31 AM, WM wrote: >> On 10.02.2025 16:16, Jim Burns wrote: >> The set F of FISONs which can be removed without >> changing the assumed result UF = ℕ >> is the infinite set F of all FISONs. > > Yes. Fine. >> This is proven by just the same induction >> as Zermelo proves his infinite set Z. >> >> Either you accept both proofs or none. >> But without there is no set theory. > > That part above is fine. > Your problem is in the step after that, > which, for some reason, you skip over. The part above defines the set of all FISONs that can be omitted without changing the union. There is no further step. > > Only a hypothetical last.FISON ͚F, > a FISON with {after.͚F} = {} > supports your reasoning: The set of all FISONs is accepted. No further restricitons allowed. > There is no last FISON. > ⋃{} ≠ ℕ That is not claimed. Claimed is only UF = ℕ ==> ⋃{} = ℕ. Can't you understand the meaning of an implication? >> No, I won't try to dive into your private notation. > > Do you accept that, > for each two FISON.numbers j′ and i′ > there exists a FISON.number maximum k′ of > i′ and the successor j′+1 of j′ > ? It is irrelevant what details exist. Induction covers the whole infinite set. > How induction works is not well known to you (WM). What is wrong in my application in your opinion? Regards, WM