$I+B$ is invertible if $B^{k} = 0$
7034
Prove that $A+I$ is invertible if $A$ is nilpotent
52113
Proof by Induction $\sum_{i=0}^{k-1} 2^i = 2^k-1$
124734
If $A^3=O$ is the matrice $A^2-A+I$ invertible?
144019
A strictly positive operator is invertible
134075
Inverse of $A^{-1}+B^{-1}$
89535
fake proof of $\forall a. \forall b. a = b \to 1 = 0$
113109
Showing that a map is bijective and finding its inverse
64747
If $A^m=I$ then A is Diagonalizable
4991
Proving by induction that $ \sum_{k=0}^n{n \choose k} = 2^n$
152817
Proving $\sup B=\inf A$
109745
If $(a,k)=(b,m)=1$, prove that $(ab,km)=(a,m)(b,k)$.
142980
If $\,A^k=0$ and $AB=BA$, then $\,\det(A+B)=\det B$
37182
If an element has a unique right inverse, is it invertible?
90402
$AB$ is not invertible
50133
The sum of odd powered real numbers equals zero implies the numbers are inverses
130268
How to prove that a nilpotent matrix is not invertible?
106398
If $A$ is invertible show that $\det(A) \neq 0$