Open sets having open images in $R^2$
66531
$\|h(x)-h(y)\|\geq 3\|x-y\|$ prove that image of open is open
101504
An open ball is an open set
152193
The intersection of a closure with an open set
47975
Closed cone in the euclidean space $\mathbb{R}^n$
85175
Continuous Images of $GL_n(\mathbb{R})$
59424
Showing that $B=\{(x,y) \in \Bbb{R^2} \mid \ xy>0 \}$ is an open set
155794
Are the complements of two homeomorphic compact, connected subsets of $\mathbb{R}^2$ homeomorphic?
72468
Open and closed balls in $C[a,b]$
48764
Increasing real valued function whose image set is connected
69542
Why do the $n \times n$ non-singular matrices form an "open" set?
91736
Explicit homeomorphism between open and closed rational intervals?
50344
What is the closure of an open ball $B_X(\mathbf{a},r)$ in $X=\mathbb{R}^n$?
74330
$\mathbb{R}^n$ not homeomorphic to open subset of $\mathbb{R}^m$
128730
Open subspaces of locally compact Hausdorff spaces are locally compact
38033
A surjective linear map into a finite dimensional space is open
152976
Real Analysis: open and closed sets
19566
Continuous images of compact sets are compact