On invertibility of a special matrix - Hilbert matrix
34576
Some questions about Hilbert matrix
124942
Prove that an upper triangular matrix is invertible if and only if every diagonal entry is non-zero.
80545
The Determinant of a Special Vandermonde Matrix
125889
Determinant of rank-one perturbations of (invertible) matrices
22222
Properties of zero-diagonal symmetric matrices
144019
A strictly positive operator is invertible
142307
Counting invertible $0$-$1$ matrices that remain invertible under negating the diagonal
19219
On the invertibility of the adjacency matrix of a graph
101313
Minimal polynomial, determinants and invertibility
125021
Inverse of an invertible upper triangular matrix of order 3
133609
orthonormal system in a Hilbert space
100257
Converse to Hilbert basis theorem
57318
Property of the conjugate transpose matrix with inner product
139087
polar decomposition of a square A when A is not full rank/invertible
18585
Showing $A-I$ is invertible, when $A$ is a skew-symmetric matrix
52791
Invertibility of an operator $T$ if $\|I-T\|<1$
110200
Determinant of a Special Symmetric Matrix