Idempotent elements in $(\mathbb{Z}_n,+,\cdot)$
7303
How many idempotent elements does the ring ${\bf Z}_n$ contain?
129239
Additive quotient group $\mathbb{Q}/\mathbb{Z}$ is isomorphic to the multiplicative group of roots of unity
147611
Given $P$ idempotent, show that $I-P$ is idempotent.
111191
Show that $P_i$ and $\sum_i P_i$ being idempotent implies $P_i P_j=\delta_{ij}$
141909
Prove ${2}^{n}\cdot(2m+1)-1 $ is invertible
73743
Number of elements in the quotient ring $\mathbb{Z}[X]/(X^2-3, 2X+4)$
146980
Zero divisors of $\mathbb{Z}×\mathbb{Z}×\mathbb{Z}$
148550
Units in quotient ring of $\mathbb Z[X]$
42810
Is $(\mathbb{Q},+)$ isomorphic to $(\mathbb{Q}^n,+)$?
22084
$\mathbb{Z}[i] / (2+3i)$ has 13 elements
53168
Surjective, Injective, Bijective Functions from $\mathbb Z$ to itself
17239
Find all ideals of ${\mathbb{Z}_n}$
19740
What's are all the prime elements in Gaussian integers $\mathbb{Z}[i]$
66134
Sufficiently many idempotents and commutativity
13355
Product of elements of a finite abelian group
1576
Finding the elements in the group of units of the ring of integers modulo n that are their own inverse.
4648
Proving that $\mathbb{Z}_m\oplus \mathbb{Z}_n \cong \mathbb{Z}_d\oplus \mathbb{Z}_l $ as groups, where $l=\mathrm{lcm}(m,n)$ and $d=\gcd(m,n)$