How do I prove that an anti-symmetric matrix $A$ is not invertible?
65158
Oddity: Determinant of Skew-Symmetric $n\times n$ Matrices
75215
Properties of invertible matrices
139087
polar decomposition of a square A when A is not full rank/invertible
30882
Proving Invertibility and Eigenvalues
141909
Prove ${2}^{n}\cdot(2m+1)-1 $ is invertible
4517
Showing a $2\times2$ matrix is invertible
54628
Properties of non-zero symmetric bilinear form
6398
Can the product of an $4\times 3$ matrix and a $3\times 4$ matrix be invertible?
61538
Given a square matrix $A$, both $AA^T$ and $A^TA$ are symmetric
33355
Proving that matrix in equation is invertible
127799
Eigenvalues of symmetric matrices are real without (!) complex numbers
112701
Prove that if matrix $A$ is nilpotent, then $I+A$ is invertible.
77941
If A, B, C, D are non-invertible $n \times n$ matrices, is it true that their $2n \times 2n$ block matrix is non-invertible?
21571
Why are real symmetric matrices diagonalizable?
120867
How prove this two symmetric matrices $AB=0$
70021
Verify if symmetric matrices form a subspace
73155
Prove that for any square matrix, an invertible matrix B exists, so that BA is triangular