Can we conclude from $MM^T=I$ that $M^TM=I $ over $\mathbb F_2$
3301
If $AB = I$ then $BA = I$
22149
How to prove $dim(Ker (A- \lambda I))=dim (Ker(A^t- \lambda I))$?
147888
Show that $M=\bigcap_{\mathfrak{p}\in\operatorname{Spec}(R)}M_\mathfrak{p}=\bigcap_{\mathfrak{m}\in\text{Max}(R)}M_\mathfrak{m}$ for certain $M$.
120035
Pattern in Isomorphisms between $\mathbb Z_m \times \mathbb Z_n$ and $\mathbb Z_{mn}$
1394
How do we know that $F = ma$, not $F = k \cdot ma$
52354
Given a idempotent endomorphism, show that $M = \ker(f) \oplus \ker (f-\text{id}_M)$
127000
When does $V = \ker(f) \oplus \operatorname{im}(f)$?
149634
$ 2|f^{'}(0)| = \sup_{z, w \in D} |f(z)-f(w)|$
84189
Is $\mathbb{C}$ equal to $\mathbb{R}^2$?
75614
Proving that $n|m\implies f_n|f_m$
145980
For every matrix $A\in M_{2}( \mathbb{C}) $ there's  $X\in M_{2}( \mathbb{C})$ such that $X^2=A$?
81181
Prove that $\det(M-I)=0$ if $\det(M)=1$ and $MM^T=I$
146455
Compactness of the set of all unitary matrices in $M_2(\mathbb{C})$
130722
Can you prove this property?
31698
$f(m^2 + f(n)) = f(m)^2 + n$ for all natural numbers
36747
$\text{Tor}_0^R(M,N)\simeq M\otimes_R N$
135511
$M_a =\{ f\in C[0,1] |\ f(a)=0 \}$ for $a$ $\in$ $[0,1]$. Is $M_a$ finitely generated in $C[0,1]$?