Showing a matrix is non-derogatory
35247
The characteristic and minimal polynomial of a companion matrix
158343
how to prove an element is non-zero in a tensor-product
134131
Squared norm of matrix equal to squared norm of its transpose
94424
Matrices and Eigenvalues of Norm
88820
Three linked question on non-negative definite matrices.
4517
Showing a $2\times2$ matrix is invertible
32103
Show that for a $2\times 2$ matrix $A^2=0$
146487
Can a non-square matrix be called "invertible"?
97487
How to prove whether a matrix has rank $1$
108955
Showing $(\mathbb{Q},+)$ is not isomorphic to $(\mathbb{R},+)$
18470
A practical way to check if a matrix is positive-definite
117769
How to show that the determinant of this matrix is in a nice product factorization,
129564
Show that $A$ is an invertible matrix if $\left(A+I\right)^3=0$ and find $A^{-1}$
116823
VERIFYING: Proving an $n \times n$ Matrix Vector Space
11911
How to prove the positive definite property of the semidefinite matrix with regularization?
64517
Prove that row rank of a matrix equals column rank
18585
Showing $A-I$ is invertible, when $A$ is a skew-symmetric matrix