Let $A$ be a Hermitian square complex matrix of size $n$ then $\langle Ax,x\rangle=0$ for all $x \in \Bbb C^n$. Then $A=0$
111550
Let $A$ be a square complex matrix of size $n$ then $\langle Ax,x\rangle=0$ for $\forall x \in \Bbb C^n$ $\iff A=0$
92774
Prove that a linear subspace of $C([0,1])$ is closed
48563
If $\Gamma^k_{ij}(p)=0$, then $\nabla_{E_i}E_j (p)=0?$
34206
Quadratic form under $\mathbb{C}$ finite-dimension vector space always have a nonzero vector that yields zero?
38635
How to prove that the matrix $A^k$ approaches $0$ as $k$ approaches infinity
1720
Show that $\langle 2,x \rangle$ is not a principal ideal in $\mathbb Z [x]$
134162
What is a basis for the space of $n\times n$ Hermitian matrices?
57166
Showing that $\Bbb R[x] / \langle x^2 + 1 \rangle$ is isomorphic to $\Bbb C$ question
131906
"An operator is hermitian". Implications?
130799
Matrix of rank 1; show that $A^2=cA$ for some scalar $c$.
114250
If $V_0$ is the subspace of matrices of the form $C=AB-BA$ for some $A,B$ in a vector space $V$ then $V_0=\{A\in V|\operatorname{Trace} (A)=0\}$
127799
Eigenvalues of symmetric matrices are real without (!) complex numbers
73677
If the matrix $A^3 = 0$, is $A$ singular?
150376
Does Real Eigenvalues mean it is an hermitian Matrix
81176
A normal matrix with real eigenvalues is Hermitian
10001
Prove that the only eigenvalue of a nilpotent operator is 0?
152102
Prove that for every complex $2$x$2$ matrix $A$, there exists a matrix $X$ such that $X^3=A^2$.