$w(T)=0 \implies T=0$?
2105
$\langle Tu\;|\;u\rangle=0,\;\forall u\in E \Longrightarrow T=0$?
34520
Is $0\,\mathrm{m}$ dimensionless?
118949
If $(Tx \mathbin{|} x) = 0$ for all $x$ then $T = 0$
52791
Invertibility of an operator $T$ if $\|I-T\|<1$
80892
Does $\wp(A \cap B) = \wp(A) \cap \wp(B)$ hold? How to prove it?
37206
$\mathbb{R}^n\times\{0\}$ has measure zero in $\mathbb{R}^{n+1}$
116389
If $\exp(t(A + B)) = \exp(tA) \exp(tB)$ for all $t \geq 0$ then $A,B$ commute
135514
$ \text{range } T' = (\ker T)^0$
75002
show that $\det(A)=0$ in this case
158335
Why is this $0 = 1$ proof wrong?
16789
Prove that $T^2$ is the zero transformation if and only if $\mathrm{range}(T) \subseteq \ker(T)$.
81181
Prove that $\det(M-I)=0$ if $\det(M)=1$ and $MM^T=I$
128026
Weak derivatives equals zero
109674
If $(I-T)^{-1}$ exists, can it always be written in a series representation?
33754
$\{T(t):t\geq 0\}$ is a strongly continuous semi-group, suppose $x\in \mathbb{X}$, $w-\lim_{t\to 0^{+}}\frac{1}{t}(T(t)-I)x=y$, show that $y=Ax$.
53364
dim$(V)$ = $n$, dim$(W)$ = $m$ $\implies$ dim($L(V,W)$) = $nm$
13899
Proof that $-v = (-1)*v$