If a ring has a left identity that is not a right identity, then there must be more than one left identity
21243
Kaplansky's theorem of infinitely many right inverses in monoids?
17997
Right identity and Right inverse implies a group
141100
Nontrivial subring with unity different from the whole ring?
61962
Show $R$ is right-Artinian but not left-Artinian
125174
Combinatorial intuition of identity
111104
Ring theory notation question
157863
A finite pseudo-ring such that $ab^2=b$ for some $(a,b)\in A$
111679
Example of a ring without unity that has a subring with unity?
46843
A ring without the Invariant Basis Number property
133738
Can a ring without a unit element have a subring with a unit element?
39724
Combinatorial Identities
17059
A ring element with a left inverse but no right inverse?
115920
Showing $R$ is a local ring if and only if all elements of $R$ that are not units form an ideal
126331
Associative ring with identity, inverses, divisors of zero and Artinianity
147079
$\gcd\left(\binom{n}{k},n\right)>1$ for nontrivial values?
125661
Two problems about rings.
130620
Identity type between A and B being non-empty implies non-emptiness of A and B?