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Questions tagged [topological-rings]

This is intended to include topological fields as well.

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8 votes
1 answer
685 views

The state of the art on topological rings - the Jacobson topology

I was recently studying the Jacobson density theorem and I found it quite interesting. Most textbooks I've seen, including Jacobson's own Basic Algebra, only spend a few lines about the reason why it ...
Melanzio's user avatar
  • 183
1 vote
1 answer
105 views

Perturbing pole of Laurent polynomial/series in a single summand

I am working with the ring of Laurent polynomials $\mathbb{F}[X,X^{-1}]$ over $\mathbb{F}$ for some algebraically closed field $\mathbb{F}$ of any characteristic. I encountered a problem emerging from ...
Jens Fischer's user avatar
1 vote
1 answer
87 views

Topological modules over a locally compact ring

Let $R$ be a locally compact, separably metrizable ring (commutative with an identity) and let $M$ be a closed submodule of $R \oplus R$. Is the projection of $M$ onto the first coordinate closed?
Nik Weaver's user avatar
  • 42.8k
11 votes
2 answers
768 views

Are topological PID's Noetherian?

Romain Giquaud has given a counterexample to the general form of the question. The bounty is for a solution for locally compact, metrizable rings. (I suspect the answer may be positive with this ...
Nik Weaver's user avatar
  • 42.8k
3 votes
1 answer
90 views

Topology of the Malcev-Neumann group ring

For a ring $R$ and a group $G$ the group ring $R[G]$ consist of maps from $G$ to $R$ with finite support. It was shown that if the group is fully ordered them this ring can be embedded in a division ...
user avatar
3 votes
1 answer
138 views

Ideals of an ordered ring

Suppose $R$ is a strictly ordered (non-commutative) ring, in particular $ab > 0$ for any $a,\, b > 0$, that is also discrete in that there are no elements between $0$ and $1$. Now consider a two-...
user avatar
2 votes
0 answers
161 views

Embedding a monoid into a group via its monoid ring

Suppose I have a monoid $(M,\, \cdot,\, e)$ equipped with a monoid homomorphism $\textrm{length} : M \rightarrow \mathbb{N}_+$ into the monoid of natural numbers under addition where $e$ is the only ...
user avatar
2 votes
0 answers
306 views

What is the status of topological problems in group rings?

I have extensively studied group rings and structure of their units and also zero divisors and normalizer problem in integral group rings.. I was pondering upon questions like what if we use ...
Bhaskar Vashishth's user avatar
3 votes
0 answers
124 views

Initial topology for a topological ring

Given a topological ring $R$ and an arbitrary (thus not necessarily surjective) epimorphism $q: R \to S$ of underlying rings is there a finest topology on $S$ such that 1) $S$ is a topological ring ...
user46484's user avatar
  • 103
7 votes
1 answer
303 views

Regular epimorphisms in the category of topological rings

I am cross-posting this question from math stack exchange (link below) as it has not received any comments or answers over the past month. A regular epimorphism is a morphism $f: X \to Y$ that is the ...
user46484's user avatar
  • 103
2 votes
0 answers
103 views

References on topological ringed spaces

This is a follow up to this question of mine. First of all, let me fix some terminologies, which may or may not be standard: Definition: A topological ringed space is a pair $X := (|X|, \mathcal{O}_X)...
Dat Minh Ha's user avatar
  • 1,516
1 vote
0 answers
330 views

Automorphisms of the topological field $\mathbb{C}_p$ of $p$-adic complex numbers?

I am interested to see what is currently known about the automorphisms of the topological field $\mathbb{C}_p$ of $p$-adic complex numbers (with respect to the $p$-adic topology induced by the $p$-...
Very Forgetful Functor's user avatar
1 vote
1 answer
50 views

S-unital compact rings are profinite

It is well-known that compact Hausdorff topological unital rings are profinite. The proof generalises to (left or right) s-unital rings (i.e. rings such that for all $r\in R$ we have $r\in Rr$ or for ...
tomasz's user avatar
  • 1,338
4 votes
0 answers
101 views

Associativity equation for topological rings and logarithms

Let $R$ be a topological ring of characteristic zero. Assume that $R$ is commutative. Let $G :R \times R \to R$ be a continuous function satisfying $G(G(x,y),z)=G(x,G(y,z))$ and $G(0,x)=x$, for all $x,...
A413's user avatar
  • 433
1 vote
0 answers
26 views

Properties of differentiable functions on non-locally-bounded fields

I was reading some results on the structure of non-locally-bounded topological fields, and I was wondering what is known about differentiable functions on them. In particular, on the complex numbers ...
dog_mu's user avatar
  • 111
4 votes
2 answers
490 views

Krull dimension of completions in non-noetherian setting (especially completed perfections)

What are some general results describing the Krull dimension of the completion of a non-Noetherian ring with a "nice" topology? An example of the sort of "nice" topological ring I'm looking for is a ...
dorebell's user avatar
  • 3,058
1 vote
0 answers
122 views

Completed Tensorproduct

I am trying to understand the completed tensorproduct. This can be defined as follows: Given a topological ring $R$ and two linearly topologized rings $A$ and $B$ with fundamental systems of open ...
slinshady's user avatar
  • 309
6 votes
0 answers
161 views

m-systems and n-systems in topological rings

Note that throughout rings have a multiplicative identity and are not necessarily commutative Definition: Let $R$ be a ring and let $M\subseteq R$. Then, $M$ is an m-system iff for every $x,y\in ...
Jonathan Gleason's user avatar
10 votes
1 answer
818 views

Is $k(\!(x,y)\!)$ a topological field?

More generally, let $(R,m)$ be a Noetherian local domain with fraction field $K$. The $m$-adic topology turns $R$ into a topological ring. When $R$ is a discrete valuation ring, this topology extends ...
Laurent Moret-Bailly's user avatar