Do epimorphisms map identity to identity?
111743
In a ring homomorphism we always have $f(1)=1$?
100107
How can I prove that a linear map $T:V\to V$ such that $T^2 = I$ is equal to the Identity map?
20547
Homeomorphism that maps given points to given points
53168
Surjective, Injective, Bijective Functions from $\mathbb Z$ to itself
143610
If $f^3=\rm id$ then it is identity function
18817
Does commutativity imply Associativity?
77563
Homeomorphism between spaces equipped with cofinite topologies
29538
Does a non-abelian semigroup without identity exist?
49924
Analytic map with two fixed points on a simply connected domain is the identity
30178
Homeomorphism $(\mathbb{CP}^1)^m/S_m \overset{\sim}{\to} \mathbb{CP}^m$?
91337
Is every self-homeomorphism homotopic to a diffeomorphism?
134104
Is there a Cantor-Schroder-Bernstein statement about surjective maps?
127664
Inverse elements in the absence of identities/associativity.
130620
Identity type between A and B being non-empty implies non-emptiness of A and B?
43626
Open Mapping Theorem: counterexample
157597
Homeomorphism between $\mathbb{Q}$ and $\mathbb{Q}(>0)$, and $\mathbb{Q}(\ge 0)$
65034
Are continuous self-bijections of connected spaces homeomorphisms?