On a finite algebra on $\mathbb{N}$
107564
If two sets have a natural (asymptotic) density, does their union?
89167
Cardinality of equivalence relations in $\mathbb{N}$
157585
Structure theorem of finite rings
89864
Units in finite polynomial rings
78412
Representing a countable field by $\Bbb N$ [transport of algebraic structure]
92822
Finite number of elements generating the unit ideal of a commutative ring
29626
Is there a proper subfield $K\subset \mathbb R$ such that $[\mathbb R:K]$ is finite?
83595
Proving that $\mathbb{A}=\{\alpha \in \mathbb{C}: \alpha \text{ is algebraic over } \mathbb{Q} \}$ is not a finite extension
150206
Every finitely generated algebra over a field is a Jacobson ring
67451
Building a bijection from a finite union of countable sets to $\mathbb{N}$
17378
Characterize finite dimensional algebras without nilpotent elements
149412
Every prime ideal of a finitely generated $\mathbb{R}$-algebra is an intersection of maximal ideals?
98897
Proving that the set of $\nu$ measurable sets $M\subseteq P(X)$ is an algebra
129109
Is the set of polynomial with coefficients on $\mathbb{Q}$ enumerable?
5699
The number of ring homomorphisms from $\mathbb{Z}_m$ to $\mathbb{Z}_n$
64408
Subgroup of $\mathbb{Q}$ with finite index
123847
Cardinality of $GL_n(K)$ when $K$ is finite