![general topology - Quotient space of closed unit ball and the unit 2-sphere $S^2$ - Mathematics Stack Exchange general topology - Quotient space of closed unit ball and the unit 2-sphere $S^2$ - Mathematics Stack Exchange](https://i.stack.imgur.com/z06VF.png)
general topology - Quotient space of closed unit ball and the unit 2-sphere $S^2$ - Mathematics Stack Exchange
![Why are the sets U and V pictured open? My understanding is that X is inheriting the subspace topology from R^2. So the basis elements are rectangles of R^2 intersecting with the Why are the sets U and V pictured open? My understanding is that X is inheriting the subspace topology from R^2. So the basis elements are rectangles of R^2 intersecting with the](https://preview.redd.it/why-are-the-sets-u-and-v-pictured-open-my-understanding-is-v0-pyykwefiazgb1.png?auto=webp&s=2ef36542fe895a1578fecadeea43e2675b2f55e4)
Why are the sets U and V pictured open? My understanding is that X is inheriting the subspace topology from R^2. So the basis elements are rectangles of R^2 intersecting with the
![functional analysis - Can we visualize the closed balls for the space $l^{\infty}$ equipped with the $\sup$ norm - Mathematics Stack Exchange functional analysis - Can we visualize the closed balls for the space $l^{\infty}$ equipped with the $\sup$ norm - Mathematics Stack Exchange](https://i.stack.imgur.com/StSEn.jpg)
functional analysis - Can we visualize the closed balls for the space $l^{\infty}$ equipped with the $\sup$ norm - Mathematics Stack Exchange
![real analysis - Show that S is non-compact and deduce further that the closed unit ball in X is non-compact. - Mathematics Stack Exchange real analysis - Show that S is non-compact and deduce further that the closed unit ball in X is non-compact. - Mathematics Stack Exchange](https://i.stack.imgur.com/BOYPV.png)
real analysis - Show that S is non-compact and deduce further that the closed unit ball in X is non-compact. - Mathematics Stack Exchange
![SOLVED: Let (X, d) be a metric space and let A be a nonempty subset of X. Given x ∈ X, define d(x, A) = inf d(x, a) | a ∈ A. SOLVED: Let (X, d) be a metric space and let A be a nonempty subset of X. Given x ∈ X, define d(x, A) = inf d(x, a) | a ∈ A.](https://cdn.numerade.com/ask_images/321046278a704ea3aa7d4679b0f4a341.jpg)
SOLVED: Let (X, d) be a metric space and let A be a nonempty subset of X. Given x ∈ X, define d(x, A) = inf d(x, a) | a ∈ A.
![metric spaces - Sketch a unit ball $B(0, 1)$ in $\mathbb{R}^2$ equipped with the following norm: $||(x, y)|| =$ max{|$x$|,|$y$|} - Mathematics Stack Exchange metric spaces - Sketch a unit ball $B(0, 1)$ in $\mathbb{R}^2$ equipped with the following norm: $||(x, y)|| =$ max{|$x$|,|$y$|} - Mathematics Stack Exchange](https://i.stack.imgur.com/sIfxb.png)
metric spaces - Sketch a unit ball $B(0, 1)$ in $\mathbb{R}^2$ equipped with the following norm: $||(x, y)|| =$ max{|$x$|,|$y$|} - Mathematics Stack Exchange
![Ball bushing unit - Linear Housing Quadro Unit - closed - VB40-808 | Ball bushing unit - Linear Housing Quadro Unit - closed - VB40-808 |Bearing units & Accessoiries | Shaft Guidance Systems | Linear Guides | Home | Dr. Tretter Ball bushing unit - Linear Housing Quadro Unit - closed - VB40-808 | Ball bushing unit - Linear Housing Quadro Unit - closed - VB40-808 |Bearing units & Accessoiries | Shaft Guidance Systems | Linear Guides | Home | Dr. Tretter](https://www.tretter.de/media/image/88/55/13/Viererbock_600x600.jpg)