# Questions tagged [ra.rings-and-algebras]

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.

**0**

**0**answers

### Flat modules and subrings

**1**

**1**answer

### Simplicial set construction of the classifying space

**0**

**0**answers

### Fundamental theorem of algebra for sedenions

**6**

**2**answers

### Is the triple product in a Freudenthal triple system fully symmetric?

**3**

**2**answers

### On submodules of vector fields

**2**

**0**answers

### Actions of rings (and other algebraic structures) on abelian categories

**1**

**0**answers

### Nilpotent elements of index $2$ in group algebra $FA_4$

**6**

**2**answers

### Different Bialgebra/Hopf algebra structures on coalgebras

**1**

**0**answers

### Finding an injective envelope containing another injective envelope

**0**

**0**answers

### Derivations of n-th Weyl algebra

**2**

**0**answers

### What comes next in the sequence "symmetric algebras, exterior algebras, divided power algebras, ..."?

**6**

**1**answer

### Solid rings and Tor

**3**

**1**answer

### Faithful flatness for rings

**4**

**0**answers

### Does the tropical semiring admit a universal property?

**1**

**0**answers

### Indecomposable comodules

**2**

**1**answer

### What is a coalgebra?

**4**

**0**answers

### Associative rings with "big" commutative subrings

**3**

**0**answers

### Homology $H_{\ast}(T, V)$

**5**

**0**answers

### Generalising supercommutativity as a grading by the $1$-truncated sphere spectrum

**8**

**0**answers

### In search of lost graded rings

**1**

**1**answer

### A closed subgroup $G$ of $\operatorname{GL}_2 \mathbb{Z}_\ell$ which surjects onto $\operatorname{GL}_2 \mathbb{F}_\ell$

**7**

**1**answer

### Separable and finitely generated projective but not Frobenius?

**2**

**0**answers

### Koszul differential of the complex $\bigwedge \mathfrak{g}^*$

**5**

**1**answer

### Are all topological (finite-dim) real vector spaces homeomorphic to a coordinate space?

**48**

**7**answers

### Good lattice theory books?

**4**

**1**answer

### A weight generalization of root systems?

**2**

**0**answers

### Hypermodulus and what mathematical objects have it

**30**

**15**answers

### Geometrical meaning of Grassmann algebra

**3**

**1**answer

### The going-up theorem for free extensions of almost commutative rings

**2**

**0**answers

### Decomposition of augmentation ideal in a group ring

**2**

**0**answers

### Extending elements of the dual of a Hopf subalgebra to the Hopf dual of the whole algebra

**10**

**1**answer

### Plane partitions as irreducible representations

**9**

**1**answer

### Are differential rings monoids in a monoidal category?

**4**

**0**answers

### Rings such that torsion-free/flat/projective modules are flat/projective/free

**4**

**0**answers

### Are PD-, $\lambda$-, $\psi$-, and $\delta$-rings monoids in a monoidal category?

**3**

**0**answers

### Efficient computation of "higher order" Jacobi symbols

**1**

**1**answer

### Using equational Jacobson condition to prove element lies in radical of ideal

**15**

**1**answer

### Defining Massey products as transgressions

**5**

**1**answer

### What is a Serre-smooth algebra?

**2**

**0**answers

### Minimizing the spectral radius of certain elements of group rings

**5**

**2**answers

### Classifying Hopf algebras that admit a single irreducible comodule

**2**

**3**answers

### The existence of two maximal ideals with the same set of idempotents

**26**

**2**answers

### Function of $(x_1,x_2,x_3,x_4)$ that factors in two ways as $\phi_1 (x_1 ,x_2 )\phi_2(x_3 ,x_4 )=\psi_1 (x_1,x_3)\psi_2(x_2,x_4)$

**3**

**0**answers

### Does the category of rings embed fully faithfully into the category of $\mathbb{F}_{1}$-algebras?

**12**

**2**answers

### Subsets of the integers which are closed under multiplication

**8**

**1**answer

### Functions over monoids which factor in two different ways

**14**

**1**answer

### Group rings such that every (countably generated) module has a maximal submodule

**5**

**2**answers

### Is this quiver with relations of finite representation type

**2**

**0**answers

### Wedderburn decomposition of wreath product of cyclic p-groups

**1**

**0**answers