What is an example of a matrix that does not represent a tensor of rank $2$?
121909
Are matrices and second rank tensors the same thing?
56312
Why can this product of rectangular matrices not be the identity matrix?
156989
Proof that Hadamard matrices of order $4k+2$ don't exist
41872
Show that $\mathbb{R}^2$ is not homeomorphic to $\mathbb{R}^2 \setminus\{(0,0)\}$
75104
Existence of some type matrix
50775
Can any linear transformation be represented by a matrix?
39334
Non-degenerate bilinear forms and invertible matrices
82688
Least rank of a matrix
11620
Is it true that any matrix in $M_2(\mathbb R)$ is the sum of two squares?
52161
Square bracket notation for anti-symmetric part of a tensor
10034
Give an example of a non-separable subspace of a separable space
28819
A union of two subspaces not equal to the vector space.
115451
What is the difference between a tensor, vector, and a matrix?
145396
Symmetric Matrix , Eigenvectors are not orthogonal to the same eigenvalue.
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
21992
Examples proving why the tensor product does not distribute over direct products.
70723
Why are nonsquare matrices not invertible?