Definition of forgetful functor
158546
In what sense is the forgetful functor $Ab \to Grp$ forgetful?
23735
Divisible module which is not injective
80260
Can it happen that the image of a functor is not a category?
100716
Zero morphism does not depend on zero object
78954
Explain a lazy evaluation quirk
122110
Character of the subobject classifier in the topos of $\mathbf{M}$-sets.
32741
Idempotents in a ring without unity (rng) and no zero divisors.
28154
Riehl's Category Theory in Context - Exercise 2.1.iv.
152354
Why is an empty set not a terminal object in categories $\mathsf{Top}$ and $\mathsf{Sets}$?
122387
Is a stably free module always free?
17378
Characterize finite dimensional algebras without nilpotent elements
132129
Derivation of derangement with inclusion-exclusion
114773
counterexamples on modules
79644
Extra }, or forgotten \right
57070
Dimensionality of null space when Trace is Zero
22644
How can I define a Listable function only apply to a vector?
43456
Can the category of chain complexes be realized as a functor category?