$Null (A) \subseteq Null(A^T A)$ if and only if $Null(A^T A) \subseteq Null(A)$
126747
Null space for $AA^{T}$ is the same as Null space for $A^{T}$
118212
Is it true that $A^A\simeq P(A)$?
110202
Is the image of a null set under a differentiable map always null?
45469
If $a_k = \operatorname{rank}(S^k)$, deduce that $a_k - a_{k+1} \geq a_{k+1} - a_{k+2}$
146364
$X$ is connected iff $\forall A\subset X,$ $\partial A\neq\emptyset$
65062
Prove $\text{rank}(A) \geq \frac{(\text{tr}(A))^2}{\text{tr}(A^2)}$ when $A$ is Hermitian
55864
Is there a null sequence that is in not in $\ell_p$ for any $p<\infty$?
124325
Element of, subset of and empty sets
2056
A space is $T_{0}$ if and only if the closures of singletons are distinct
56399
Proof for $A \cup B = B$ if and only if $A \subset B$
41080
If A, B, and C are set and $A \subset B ,B \subset C \rightarrow A \subset C$
70468
Row space and column space of $A^T A$ and $A A^T$
8082
What is A Set Raised to the 0 Power? (In Relation to the Definition of a Nullary Operation)
93157
If $A \subseteq B$, does $\mbox{dist}(x,\partial A) \le \mbox{dist}(x, \partial B)$ hold for all $x \in A$
151168
dist$(x,A)=0$ if and only if $x\in \overline{A}$ (closure of $A$)
134914
Let $A,B$ and $U$ be sets so that $A\subseteq U$ and $B\subseteq U$. Prove that $A\subseteq B$ iff $(U\setminus B)\subseteq(U\setminus A)$.
27368
(Verification) $C \approxeq A$ or $C \approxeq \text{section of } A$ $\forall C$ s.t. $C \subset A$