List questions from rngs | MathQA

Simple example for a rng with an inverse semi-group as the multiplicative group

Published on 25 Mar 2026 - 7:47

Nontrivial subring of $\mathbb{R}$ not containing $1$

Published on 29 Aug 2020 - 1:50

In a finite commutative ring , every prime ideal is maximal?

Published on 29 Aug 2020 - 18:42

Structural differences between $2 \mathbb{Z}$, $3 \mathbb{Z}$ as rings.

Published on 31 Oct 2020 - 6:15

Can the union of an ascending sequence of ideals of $R$ be $R$?

Published on 22 Dec 2020 - 0:48

How can you prove Nakayama's lemma over nonunital rings using the unitization?

Published on 18 Jan 2021 - 23:08

$R$ a non-unitary ring such that $R^+ \cong \mathbb{Q}/\mathbb{Z}$

Published on 15 Jul 2021 - 10:21

If ring $R\neq \{0\}$ then subring $R_0 \neq \{0\}$ (proof verification)

Published on 21 Jul 2021 - 15:24

Looking for counterexamples (non-domains)

Published on 22 Jul 2021 - 15:06

Formula for two sided principal ideal for a ring without unity

Published on 31 Aug 2021 - 16:04

Can $\mathbf{Rng}$ be made into a pre-additive category?

Published on 24 Mar 2026 - 5:32