Not being well-versed in the area, I looked up
"Kissing Number" at Mathworld.
In the table, I notice that the "NL" (non lattice
kissing number) values are missing
for dimensions 1 thru 8. Don't we know that NL(1,2,3) = (2,6,12)? And
certainly
at worst NL(d) >= L(d) for d = 4 thru. I
gather from our current discussion that we
know 24 = L(4)
<= NL(4) <= 25, and are discussing means to establish or
eliminate
NL(4) = 25 (though I've been following the thread
only cursorily). Do we know of
any lower bounds better than NL(d) for d <= 8
that we might put in the table?
Also, bear with me here, I'm going to rehash some
elementary stuff. In 2
dimensions, we easily see that a unit circle
kissing unit circle S "uses up" pi/3
radians of the circumference of S, which cannot be
used by any other kissing
circle. This bounds NL(2) <= (2pi)/(pi/3)
= 6. Similarly, a unit sphere
kissing
unit sphere S "uses
up" an area A of the surface of C subsumed by a circle
with a 60-degree diameter, so that NL(3) <=
(4pi)/A. Does this observation
generalize to higher dimensions? Does it
result in an upper bound formula
for NL(d)? Is there a nice bounding
asymptotic? Does the formula grow
relatively worse or better for increasing d?
I'm sure this is textbook, but I've
never seen it developed. If there is an
accessible online development, that
would be great.