2
votes
1answer
104 views
Is there an “accepted” jamming limit for hard spheres placed in the unit cube by random sequential adsorption?
I have a unit cube, and operating in the continuum limit (i.e. not on a lattice), I sequentially place spheres of some radius $r$ inside the cube until a filled volume "jamming lim …
5
votes
2answers
193 views
Kissing Number of Spheres in Non-Euclidean Geometry
There has been much work done on the kissing number problem (of determining the greatest number of congruent spheres which can touch a single sphere in a packing) in Euclidean spac …
10
votes
0answers
405 views
How many unit balls can be put into a unit cube?
Here a unit ball is a ball of diameter 1, and a unit cube is a cube of edge length 1.
A famous counterintuitive fact is that, as the dimension increases, the volume of the unit ba …
20
votes
2answers
531 views
The kissing number of a square, cube, hypercube?
How many nonoverlapping unit squares can (nonoverlappingly) touch one unit square?
By "nonoverlapping" I mean: not sharing an interior point.
By "touch" I mean: sharing a boundary …
2
votes
0answers
116 views
Computing the Volume of Closed 3-Manifolds and the Geometrization Conjecture
My question is whether or not if I generalize Theorem 2(i) of "Contact Graphs of Unit Sphere Packings Revisited" [2012] by K. Bezdek and S. Reid (arXiv link) which states
The n …
2
votes
1answer
93 views
Packing a closed 3D surface with non-overlapping spheres starting with the largest possible one and then working the way down
Let's say, I have a closed 3D surface (say, the surface of a pebble). I want to pack it with spheres, but starting with the largest possible sphere, then the next largest possible …
0
votes
1answer
112 views
Optimal fitting of spheres in a cylinder.
how to find the minimum height and width of a cylinder containing n identical spheres?
30
votes
6answers
904 views
Tetris-like falling sticky disks
Suppose unit-radius disks fall vertically from $y=+\infty$,
one by one, and create a random jumble of disks above the $x$-axis.
When a falling disk hits another, it stops and stick …
9
votes
4answers
624 views
Optimal pebble-packing shape
Suppose you throw many ($n$) congruent convex bodies (in $\mathbb{R}^3$) of unit volume (or of unit area in $\mathbb{R}^2$) into a large container, and shake it until little else c …
2
votes
1answer
231 views
What are some properties of Delone sets that come from Barlow packings of spheres?
Given a Barlow packing of $\mathbb{R}^n$ by balls with at most a finite number of different radii, the centers of the balls will form a Delone set in $\mathbb{R}^n.$
For a highes …
19
votes
6answers
1k views
Covering a unit ball with balls half the radius
This is a direct (and obvious) generalization of the recent MO question, "Covering disks with smaller disks":
How many balls of radius $\frac{1}{2}$ are needed to cover complet …
1
vote
0answers
156 views
Which term is better for the so called “sphere packing”?
I'm working on sphere packings. When I write, I'm confused with basic definitions. I'm hesitating between the terms "sphere", "ball" or "oriented sphere".
For example, on the wiki …
10
votes
2answers
397 views
What is the largest possible thirteenth kissing sphere?
It is well-known that it is impossible to arrange 13 spheres of unit radius all tangent to another unit sphere without their interiors intersecting. This was apparently the subjec …
4
votes
1answer
157 views
Inter-Kissing Number for Spheres of Different Sizes
What is the maximum number of spheres that can be placed in 3D such that all inter-touch?
One can of course place four unit spheres tetrahedrally and then add a smaller sphere in …
1
vote
0answers
189 views
maximal minimum distance in a sphere packing
Hi everyone.
I need to pick a set of 65 points p(x,y,z) in a 3D space of 274625 points; as
the set picked should provide the maximum possible minimum Hamming distance.
(Consider th …

