Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 36721
3 votes
Accepted

Dividing a spherical cap into three equal wedges

Let $f(s)$ stand for the difference between the left- and right-hand sides of your displayed inequality. We want to show that $f<0$ on the interval $(0,1/ \sqrt3)$. Let $$f_1(s):=f'(s)\frac{8 \sqrt{1- …
Iosif Pinelis's user avatar
2 votes
Accepted

Inner Products of Elements in Spherical Cap

Yes, this follows immediately from the triangle inequality on the sphere -- cf. e.g. this or this.
Iosif Pinelis's user avatar
3 votes
Accepted

The mean of positive points on a unit $n$-sphere $S^n$

The answer is no. E.g., let $P$ be the set $\{1,e^{it},e^{i3t}\}$ of points on the unit circle in $\mathbb C=\mathbb R^2$, where $t$ is a small positive real number. Then the geodesic mean of $P$ is $ …
Iosif Pinelis's user avatar
1 vote
Accepted

Let $\alpha\in(0,1),d\in\mathbb N^+$ and $X,Y\in\mathbb S^d$ be uniform, what is $\Pr[\lVert...

$\newcommand\al\alpha$By spherical symmetry, the conditional distribution of $\|X-Y\,\sqrt{1-\al}\|$ given $Y$ does not depend on $Y$. So, letting $e_1:=(1,0,\dots,0)$ and writing $X=(X_1,\dots,X_d)$, …
Iosif Pinelis's user avatar
5 votes
Accepted

Probability that three vectors of a unit sphere lie on one side of a hyperplane if angle bet...

$\newcommand\al\alpha\newcommand\be\beta\newcommand\ga\gamma$It appears that the question is as follows: Given unit vectors $a,b,c$ with angles $$\al:=\cos^{-1}(b\cdot c),\quad \be:=\cos^{-1}(a\cdot c …
Iosif Pinelis's user avatar
0 votes

Decreasing magnitude of spherical centroid

$\newcommand{\R}{\mathbb R}\newcommand{\SSS}{\mathbb S}\newcommand{\tS}{\tilde S}\newcommand{\tR}{\tilde R}$This is to detail and formalize the nice counterexample outlined in fedja's comment. First, …
Iosif Pinelis's user avatar