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Non-commutative rings and algebras, non-associative algebras, universal algebra and lattice theory, linear algebra, semigroups. For questions specific to commutative algebra (that is, rings that are assumed both associative and commutative), rather use the tag ac.commutative-algebra.

3 votes
1 answer
228 views

An isomorphic invariant in ring theory

Let $R$ be a unital ring. We define the Murray Von Neumann relation $M$ on $R$ as follows: We say $a M b$ iff $a=xy,\;b=yx$ for some $x,y\in R$. (This is inspired by the usual Murray Von Neumann eq …
Ali Taghavi's user avatar
4 votes
2 answers
567 views

Some examples of clean topological spaces

I asked this question at MSE but I did not received any answer, so I repeat it here at MO: What is an example of a Hausdorff topological space $X$, not a singleton, such that the ring $C(X) …
Ali Taghavi's user avatar
3 votes
2 answers
164 views

Is the pair $(C([0 \;1]),\mathbb{C})$ a consecutive pair?

Motivated by this post we give the following definition: Definition: A pair of unital rings $(R,S)$ is called a consecutive pair of rings if they do not have non trivial idempotent and …
Ali Taghavi's user avatar
1 vote
1 answer
303 views

A question in ring theory

Is there an example of two groups $G_{1}, G_{2}$ such that there are two non isomorphic ring $R_{1}$ and $R_{2}$ such that the additive group of both rings is isomorphic to $G_{1}$ and their unit gro …
Ali Taghavi's user avatar
1 vote
0 answers
104 views

Hochschild coboundary on the space of alternative forms

Assume that $A$ is a complex algebra. By $C^{n}(A)$ we mean the space of all $n-$linear map $\phi:A^n \to \mathbb{C}$. An alternative $k-$ form is an element $\phi \in C^{k}(A)$ …
Ali Taghavi's user avatar
1 vote
0 answers
134 views

Non commutative analogy of compact-open topology

Let $R$ be a ring, define a topology on $AUT(R)$(Or End(R)) with the following subbase: For every two 2-sided Ideal $I$ and $J$, a subbase element is $B(I,J)=\{f\in AUT(R) \mid f(I)+J=R\}$. We can re …
Ali Taghavi's user avatar
1 vote
1 answer
304 views

Simple $C^*$ algebras whose all commutator elements have scalar square

Is there a simple $C^*$ algebra $A$, not isomorphic to $M_2(\mathbb{C})$, such that for every commutator element $x=ab-ba$, $x^2$ is an scalar element?
Ali Taghavi's user avatar
2 votes
0 answers
301 views

A question on Giles Gardam counter example to the Unit conjecture of Kaplansky

The unit version of the Kaplansky conjecture is about units in $FG$ where $F$ is a field and $G$ is a torsion free group. In a recent counter example by Giles Gardam, it is given an e …
Ali Taghavi's user avatar
4 votes
2 answers
659 views

Modules over infinite rings which can not be a finite union of their proper submodules

It is well known that a vector space over an infinite field cannot be a finite union of its proper subspaces. Does this fact have an immediate and obvious generalization to modules over infinite di …
Ali Taghavi's user avatar
7 votes
0 answers
637 views

Row rank and column rank of matrix with entries in a commutative ring

Let $R$ be a unital commutative ring and $A\in M_{n\times m}(R)$. Under which appropriate invariant "rank" of modules discussed in "Ranks of Modules" one can say that the row rank of $A$ is …
Ali Taghavi's user avatar
0 votes
1 answer
185 views

A subset (or subgroup) associated to a group

Edit: According to comment conversations we revise the question. Let $G$ be a group. We consider the following subset of $G$: $$\{g\in G \mid e^{\lambda_g} \in \mathbb{C}\lambda (G)\},$$ where $\lamb …
Ali Taghavi's user avatar
1 vote
1 answer
185 views

Is a finite dimensional graded algebra isomorphic to the equivariant de Rham complex of a Li...

Edit: According to essential comment of YCore I revise the question. Let $A$ be a finite dimensional graded algebra which is a unital, super commutative and associative algebra. Is there a Lie group …
Ali Taghavi's user avatar
1 vote
0 answers
177 views

A locally convex $C^*$ algebra without zero divisor

Let we have a locally convex $C^*$ algebra $A$. That is $A$ is a TVS equipped with an algebra and an involution structure such that all operations are continuous. Moreover the topology on $A$ i …
Ali Taghavi's user avatar
2 votes
0 answers
88 views

Non-existence of idempotent via evaluation of higher order cocycle on a tuple of idempotents

The Kaplansky conjecture and Kaplanski-Kadison conjecture are classical conjectures about non existence of non-trivial idempotents in group algebra $\mathbb{C}\Gamma $ or the reduced group algebra …
Ali Taghavi's user avatar
1 vote
0 answers
112 views

Idempotent conjecture and non-abelian solenoid

Is there a discrete non-abelian group whose dual in a reasonable sense is isomorphic to the solenoid constructed via a sequence of quaternions $S^3$ instead of a sequence of circles? The motivation c …
Ali Taghavi's user avatar

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