# 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.

**4**

**1**answer

### Tensor product of positive linear maps is positive

**9**

**2**answers

### Global homological dimension of group rings

**3**

**0**answers

### Adic completion of quotient

**1**

**1**answer

### If, in a unit-regular ring, the right annihilator of $a$ equals the right annihilator of $b$, then $aR = bR$?

**1**

**0**answers

### quantum affine $gl_2$

**3**

**2**answers

### Low dimensional noncommutative non-cocommutative Hopf algebras

**0**

**0**answers

### Is there a roadmap to learning representation theory of finite group over finite field?

**31**

**8**answers

### Uncountable counterexamples in algebra

**13**

**1**answer

### Existence of a translation-invariant basis of $\ell^2$

**4**

**0**answers

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

**7**

**0**answers

### Is this “semi-tensor product” something recently invented? Are there other usages of it?

**17**

**3**answers

### Existence of translation-invariant basis on $C_c(\mathbb R)$

**2**

**0**answers

### Lie Groups and Lie algebras related to Jordan algebras

**2**

**0**answers

### On the use of the fundamental exact sequence of K\"ahler differentials in a paper of Lyubeznik

**9**

**1**answer

### Special nilpotent elements

**0**

**0**answers

### Levi decomposition for associative algebras

**2**

**0**answers

### Base change to algebraic closure commutes with quotient of polynomial ring by maximal ideal

**2**

**0**answers

### Socle of a quotient of the ring of differential operators of a polynomial ring

**10**

**2**answers

### Are the trace relations among matrices generated by cyclic permutations?

**4**

**1**answer

### Can all finite-dimensional noncommutative algebras with trace be trace-preserving embedded into matrix rings?

**-3**

**0**answers

### Did anyone ever propose a hypercomplex numbers system with more than one anisotropic axis? [closed]

**0**

**0**answers

### Can the notion of algebraic closedness be generalized to the rings with zero divisors?

**0**

**0**answers

### How to classify rings by combinatorial structures?

**9**

**1**answer

### Mistake and correction-Drozd, Y.A., Kirichenko, V.V.: Finite Dimensional Algebras

**1**

**0**answers

### Faithfull flatness of a module containing the ring as a direct summand

**1**

**0**answers

### Free monoids on posets

**1**

**0**answers

### Construction, similar to Chow's EL-numbers? Is it valid? What are the properties?

**2**

**1**answer

### English translation of Emmy Noether's Hyperkomplexe Grössen und Darstellungstheorie

**7**

**0**answers

### Is there a reasonable definition of an octonionic manifold?

**18**

**2**answers

### Why does Drinfeld Unitarization work?

**3**

**1**answer

### Is a comultiplication structure unique?

**5**

**3**answers

### Unital *-homomorphisms between matrices

**3**

**2**answers

### Is there any simple formula for the character of $S_{n}$ represented by the set of $k$-tuples of $\{1,2,…,n\}$?

**5**

**1**answer

### Explicit construction of division algebras of degree 3 over $\mathbb{Q}$

**3**

**0**answers

### Bound quiver algebras with relations of the form $x_ix_j=$sum of paths of length $\geqslant 3$

**1**

**0**answers

### Morphism of R-algebras between R-adic algebras

**2**

**1**answer

### About extensions between morphisms on the multiplier algebra

**1**

**1**answer

### Non-degeneracy of comultiplication (multiplier Hopf algebras)

**5**

**1**answer

### Invariant ideal generated by invariant elements

**1**

**1**answer

### Antipode on a multiplier Hopf-algebra

**2**

**0**answers

### Examples of multiplier Hopf algebras

**5**

**0**answers

### Representation theory terminology question

**4**

**2**answers

### Embedding of a division algebra into a matrix algebra over its centre

**2**

**0**answers

### Is there a characterisation of Cayley–Dickson Algebras?

**1**

**0**answers

### How can we prove a specific isomorphism between graded Lie algebra and graded universal enveloping algebra?

**1**

**1**answer

### A comodule algebra map from a Hopf algebra to itself

**3**

**1**answer

### Number of rings with additive group $(\mathbb{Z}_{16})^2$. A341547(16) in OEIS

**2**

**0**answers

### Explicit example of prime ideal not an intersection of maximal ideals, in universal enveloping algebra

**3**

**1**answer

### What is the $p$-regular partition corresponding to the sign representation of $S_{n}$ over a field of characteristic $p$?

**3**

**1**answer