Showing there is a natural map between coim$(f)$ and im$(f)$ in an abelian category
74617
Equivalent conditions for a preabelian category to be abelian
53176
Intuitive Approach to de Rham Cohomology
55488
Proving that $\operatorname{codim}(X,Y)=\dim(\mathcal{O}_{X,\eta})$
111129
Show that $[K:F]_s = [K:L]_s [L:F]_s$ and $[K:F]_i = [K:L]_i [L:F]_i$.
97608
Showing a Ring of endomorphisms is isomorphic to a Ring
17978
Isomorphism classes of $\mathbb{Z}[i]$ modules.
25383
Morphism between quotient sheaf ($K_{X}/\mathcal{O}_{X}$) and $\bigoplus_{x\in\mathcal{X}}i_{x,*}(K(X)/\mathcal{O}_{X,x})$
145462
On the canonical isomorphism between $V$ and $V^{**}$
129162
Show there is a surjective homomorphism from $\mathbb{Z}\ast\mathbb{Z}$ onto $C_2\ast C_3$
61593
Adjoint map is Lie homomorphism
8374
How to prove that $R/I \otimes_R M \cong M / IM$
127000
When does $V = \ker(f) \oplus \operatorname{im}(f)$?
60731
Factorization of a map between CW complexes
28324
Inverse image of the sheaf associated to a module
145339
Index of the subgroup $\operatorname{Im}(f)$
123130
Showing an isomorphism between exterior products of a free module
151993
Ring homomorphisms $\mathbb Z[x]\rightarrow \mathbb Q$