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May 12, 2018 at 21:12 history edited Luc Guyot CC BY-SA 4.0
non-associated (distinct in $R/R^{\times}$) is more precise than "distinct"
May 12, 2018 at 20:22 comment added Luc Guyot @users I have now added a proof of Claim 5.
May 12, 2018 at 20:21 history edited Luc Guyot CC BY-SA 4.0
Added a proof of Claim 5
May 12, 2018 at 15:53 comment added user111524 In your claim 5, is $R$ really any non-field integral domain (no UFD or extra assumption?) ? I don't see how does it follow ...
Apr 8, 2018 at 0:03 history edited Luc Guyot CC BY-SA 3.0
Fixes Corollary 2's statement and proof
Apr 7, 2018 at 22:33 history edited Luc Guyot CC BY-SA 3.0
Erratum for Corollary 2
Jan 9, 2018 at 21:21 comment added Luc Guyot @users Yes if $R$ is a UFD, but I have no idea in general. Considering examples may help.
Jan 7, 2018 at 18:24 comment added user111524 We know that $S_R$ is always saturated. Let $\hat S_R$ be the multiplicative submonoid generated by $S_R$ and the unit of $R$; is $\hat S_R$ still saturated ?
Dec 6, 2017 at 13:00 comment added Luc Guyot This is just enough as such prime is maximal.
Dec 6, 2017 at 12:56 comment added user111524 If $a$ is a product of prime elements then why would $\mathfrak m$ be a principal ideal generated by one of them ? I can only see that $\mathfrak m$ contains a principal ideal generated by one of them ...
Dec 5, 2017 at 20:44 comment added Luc Guyot Oops, this is a non-zero element of $\mathfrak{m}$, just corrected.
Dec 5, 2017 at 20:43 history edited Luc Guyot CC BY-SA 3.0
Fixes typo: $a$ belongs to $\mathfrak{m} \setminus \{0\}$.
Dec 5, 2017 at 20:22 comment added user111524 what is your $a$ in the argument ?
Dec 5, 2017 at 20:20 comment added Luc Guyot Every Abelian group is isomorphic to the ideal class group of some Dedekind domain, so the answer is no in general, although it holds for rings of integers. The only hypothesis is that $R$ is not a PID, so it has a non-principal maximal (= non-zero prime) ideal.
Dec 5, 2017 at 19:49 comment added user111524 Is every maximal ideal class an element of finite order in the ideal class group of a Dedekind domain ? (you seem to be using so in your corollary about ideal class groups)
Nov 14, 2017 at 22:41 history edited Luc Guyot CC BY-SA 3.0
Simplifies the proof of the "Corollary" and corrects the description of $S_R$ for an atomic domain $R$.
Nov 14, 2017 at 22:39 comment added Luc Guyot @users I simplified the proof of the corollary. Since a Dedekind domain $R$ is atomic, $S_R$ is generated by the units of $R$ and the prime elements $p$ such that $Rp$ is a maximal ideal.
Nov 14, 2017 at 22:35 history edited Luc Guyot CC BY-SA 3.0
Simplifies the proof of the "Corollary"
Nov 11, 2017 at 14:12 comment added user111524 I had some difficulty understanding your corollary about ideal class groups. How do you get that there is a maximal ideal whose ideal class is non-trivial and has finite order ? I can see that from $\mathcal m^n=Ra$ , and $\mathcal m$ not principal, we can conclude that $a$ is not a product of primes, but how does that imply that $a \notin S_R$ ?
Oct 24, 2017 at 16:10 comment added Luc Guyot @users It is quite the same to me. My 2 cents: relax the atomic assumption until it breaks mulitplicative closedness. You may find then (counter)examples which are GCD or Prüfer.
Oct 16, 2017 at 12:39 comment added user111524 Okay ... what about Prufer domains ?
Oct 16, 2017 at 9:37 comment added Luc Guyot @users I am unable to show anything assuming $R$ is a GCD. If I had time, I would try to generalize the claim about multiplicative closedness to some generalizations of atomic rings ("Non-Noetherian commutative ring theory" by S.T. Chapman and S. Glaz looks like a good place to start from) and strive for the search of a non-atomic counter-examples.
Oct 12, 2017 at 19:42 comment added user111524 Assuming $R$ is a GCD domain i.e. $Ra \cap Rb$ is a principal ideal for every $a,b \in R$ , (en.wikipedia.org/wiki/GCD_domain) , can you show that $S_R$ is multiplicatively closed ? Assuming $R$ is a Prufer domain , (en.wikipedia.org/wiki/Pr%C3%BCfer_domain) , can you show that $S_R$ is multiplicatively closed ?
Sep 28, 2017 at 8:38 vote accept CommunityBot
Sep 21, 2017 at 6:47 history edited Luc Guyot CC BY-SA 3.0
Removes superfluous right brace
Sep 20, 2017 at 21:36 history edited Luc Guyot CC BY-SA 3.0
Fixed typo in the proof of Claim 2 and added further references to Wiki pages for definitions
Sep 20, 2017 at 19:31 history edited Luc Guyot CC BY-SA 3.0
Fixes typo in the proof of the top Corollary
Sep 20, 2017 at 19:27 comment added Luc Guyot @users The typo is now corrected, thanks. I expanded my answer by giving an example of ring $R$ such that $R^{\times} \subsetneq S_R \subsetneq R \setminus \{0\}$.
Sep 20, 2017 at 19:23 history edited Luc Guyot CC BY-SA 3.0
Gives an explicit example of set $S_R \subsetneq R \setminus \{0\}$
Sep 20, 2017 at 16:49 history edited Luc Guyot CC BY-SA 3.0
Gives a non-trivial example of multiplicative set $S_R$
Sep 2, 2017 at 16:31 history edited Luc Guyot CC BY-SA 3.0
Fixes typo spotted by 'users'
Sep 2, 2017 at 13:01 comment added user111524 Your proof of claim 2 still contains a typo .. $1$ can be written as a linear combination of $p$ and $x$ , not $a$ and $x$ ... as far the motivation of the question regrads , I was just tryinv to see various properties related to domains having some good factorial or arithmetical prooerties and then trying to isolate the elements with special properties ... I am thinking about vatious othet related properties , I will post about it here if I need help seeing as good a response as yours ...
Sep 1, 2017 at 17:11 comment added Luc Guyot @users I corrected and simplified the proof of Claim 2.
Sep 1, 2017 at 17:08 history edited Luc Guyot CC BY-SA 3.0
Corrected and simplified the proof of Claim 2
Aug 31, 2017 at 16:15 comment added Luc Guyot @users I just added Claim 5 which also relates to your new question.
Aug 31, 2017 at 16:14 history edited Luc Guyot CC BY-SA 3.0
Added Claim 5 about multi-variate polynomials and an instance of $S_R \neq N_R$
Aug 30, 2017 at 23:17 history edited Luc Guyot CC BY-SA 3.0
Fixes claim about regular local ring
Aug 30, 2017 at 23:12 history edited Luc Guyot CC BY-SA 3.0
added 83 characters in body
Aug 30, 2017 at 21:51 history edited Luc Guyot CC BY-SA 3.0
Fixed typo ($x'$ instead of $e$), removed useless mention to $R$, removed obsolete sentence
Aug 30, 2017 at 21:46 history edited Luc Guyot CC BY-SA 3.0
Fixed typo ($x'$ instead of $e$), removed useless mention to $R$
Aug 30, 2017 at 21:26 history edited Luc Guyot CC BY-SA 3.0
Widen the scope of Corollary 2
Aug 30, 2017 at 21:23 comment added Luc Guyot @users I just modified my answer to settle the case of atomic domains. It answers your new question for domains which satisfy the ascending condition on principal ideals.
Aug 30, 2017 at 21:13 history edited Luc Guyot CC BY-SA 3.0
Added a wiki link for atomic domains
Aug 30, 2017 at 21:00 history edited Luc Guyot CC BY-SA 3.0
widen the scope of the answer to atomic domains
Aug 30, 2017 at 20:40 history edited Luc Guyot CC BY-SA 3.0
Rewording of a sentence in the proof of Claim 3
Aug 30, 2017 at 20:13 history edited Luc Guyot CC BY-SA 3.0
Positive answer in the Noetherian case
Aug 30, 2017 at 20:07 history edited Luc Guyot CC BY-SA 3.0
Positive answer in the Noetherian case
Aug 30, 2017 at 19:58 history edited Luc Guyot CC BY-SA 3.0
Positive answer in the Noetherian case
Aug 30, 2017 at 17:11 history edited Luc Guyot CC BY-SA 3.0
Added Corollary 2 about Noetherian local domains
Aug 29, 2017 at 20:22 history edited Luc Guyot CC BY-SA 3.0
Add remarks about the case of a local domain
Aug 29, 2017 at 10:15 comment added user111524 Suppose for an integral domain $R$ , the set in the question say $S_R$ is multiplicatively closed ; then is $S_{R[X]}$ also multiplicatively closed in $R[X]$ ? (We already know it is saturated ... )
Aug 29, 2017 at 10:05 comment added user111524 Here is the proof that the set you mention (call it $S$ say) is saturated : Let $ab \in S$ and let $t\in R$ ; then either $ab | tb $ or $tb | ab$ ; now , since $b \neq 0$ , so if $ab | tb$ then $a|t$ and if $tb |ab$ then $t|a$ ; so either $a|t$ or $t|a$ and $t \in R$ was arbitrary , so $a \in S$
Aug 29, 2017 at 0:41 history edited Luc Guyot CC BY-SA 3.0
deleted 7 characters in body
Aug 29, 2017 at 0:36 history edited Luc Guyot CC BY-SA 3.0
Corrects assumption of Claim 2; edited body
Aug 28, 2017 at 21:37 history edited Luc Guyot CC BY-SA 3.0
Fixed Claim 2
Aug 28, 2017 at 21:27 history edited Luc Guyot CC BY-SA 3.0
Existence of constant $u$-polynomial is trivial.
Aug 28, 2017 at 21:16 history edited Luc Guyot CC BY-SA 3.0
Precise reference to Weintraub's example
Aug 28, 2017 at 21:09 history edited Luc Guyot CC BY-SA 3.0
Added Claim 2 as an application of Claim 1 to polynomial rings over domains
Aug 28, 2017 at 18:00 history edited Luc Guyot CC BY-SA 3.0
Fixes "saturation" and typo
Aug 28, 2017 at 15:35 comment added user111524 I also don't know of any examples ... but that shouldn't stop us from trying to prove or disprove the claim ... your proof of saturated ness is nice and simple , though I know this trick , I totally missed it here ..
Aug 27, 2017 at 21:25 history edited Luc Guyot CC BY-SA 3.0
Removes signs of uncertainty
Aug 27, 2017 at 20:54 history edited Luc Guyot CC BY-SA 3.0
Right multiplication is more consistent
Aug 27, 2017 at 19:56 history answered Luc Guyot CC BY-SA 3.0