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1 vote
2 answers
349 views

How many non-isomorphic associative algebras of dimension 2 over the field F_{p^k} are there?

How many non-isomorphic associative algebras of dimension 2 over the field F_{p^k} are there? As much as I have searched, I have not found any results that answer my question; not even for k = 1,2.
José María Grau Ribas's user avatar
6 votes
1 answer
328 views

Algebra with a certain abelian group as the multiplicative group

Let $A$ be an abelian group. Are there an algebra $\mathfrak{X}(A)$ s.t. the multiplication group is isomorphic to A ? i.e. $$ \mathfrak{X}(A)^{\times} \simeq A. $$ For example, for $A=\mathbb{Z}/4\...
M masa's user avatar
  • 479
2 votes
1 answer
290 views

Endomorphism rings of infinitely generated free modules generated by idempotents?

Let $M$ be a free right $R$-module. When $M_R\cong R_R^n$ with $n\in \mathbb{Z}_{\geq 1}$, then we know that the endomorphism ring $E={\rm End}(M_R)$ is isomorphic to $\mathbb{M}_n(R)$. We also know ...
Cary's user avatar
  • 23
2 votes
2 answers
103 views

Uniqueness of character for Z_+-rings

I have a question about the proof of proposition $3.3.6(3)$ in "Tensor Categories" by Etingof et al.. This part states that for $A$, transitive unital $\mathbb Z_+$-ring, there is a unique character ...
DerLoewe's user avatar
5 votes
1 answer
271 views

Where can we find polynomial's root?

Let $R$ be a ring (not commutative in general) with identity and let $\Psi(x) = x^m-\sum_{j=0}^{m-1}\psi_jx^j$ be a monic polynomial over $R$. I want to construct a ring extension $K$ of $R$, which ...
Mikhail Goltvanitsa's user avatar
7 votes
1 answer
1k views

Whether a given algebra is the algebra of endomorphisms for a vector space

Let $\mathbb{F}$ be a field and let $A$ be an associative unital $\mathbb{F}$-algebra. Is there a criterion to let me know if $A$ is isomorphic to the algebra $\mbox{End}(\mathbf{V})$ of endomorphisms ...
Bedovlat's user avatar
  • 1,959
-1 votes
1 answer
246 views

Maximal commutative subrings of the endomorphism ring of a vector space

Let $\mathbb{F}$ be a field, and $\mathbf{V}$ a possibly uncountably generated $\mathbb{F}$-vector space. Let $\mbox{End}_\mathbb{F}(\mathbf{V})$ be the endomorphism ring of $\mathbf{V}$. That the ...
Bedovlat's user avatar
  • 1,959