Sunday, July 15, 2007

##

Imagine a circle inscribed in a square. Imagine a sphere inscribed in a cube.

Trust that there are wise and coherent ways of extending such a situation beyond the three axes of comprehensible space.

Imagine, in colors, or as a mash of nonsense if you like, a prickly urchin of n mutually perpendicular axes, demarcating and graduating the points of n dimensional space. To soothe the skeptic, let's say that we only mean that each point is an ordered set (bing, bong, bling,....) of n real numbers, and that a cogent definition of distance applies to relate these creatures to one another.

We will recover the evolved version of the above geometric scenario, translated to this new more airy arena.

The solid sphere that lives in n-space is the smooth haze around the center of the the axis-urchin, those points of distance at most one from the origin, (a characterization which captures, you might note, the essential physiognomy of his more intuitive cousins).

The autochthonous cube of dimension n is the box made by erecting a perpendicular obstruction at the unit points of all n coordinate staves, then regarding with satisfaction the consequent area enclosed. Another, less scenic, conception can be had by considering locations of the form (a,b,c, ..., z) where the letters have value between one and one negated.

Now.

We have, if you will look and see with me, a hypercube which inscribes a hypersphere. What can we say about it?

It has a strange feature.

We notice that in the sigil of the circle inscribed in a square, and the sphere nestled in its cozy box, that the accommodations are not excessively spacious. These simple orbicles have scarcely room in their restrictive housings to turn around. To be vulgar, the sphere in the box occupies 52 percent of the area boxily bounded (the circle slightly more).


But upstairs, in the expanded inflated volumnized world of high dimensionality, this intuition is broken, snapped, severed, inapplicable. The sophisticated descendants of the provincial ball and box stand in a much less egalitarian relation.

The sphere, sadly, for sufficiently rarified values of n, occupies a vanishing portion of its home. It becomes like the lonely occupant of a mansion, then a mote of dust drifting by a window, and then is lost to all scrutability, vanishing down into quark-like insignificance, an angel on the head of a pin.

All the while, it abuts just as belligerently against the confines of its surrounding box as happened in dimensions one and two.

There is, therefore, a wonderful mystery about simple geometrical objects with great extension. Unfortunately it is not our province to know these beings. We glimpse them only unsatisfactorily as they drift through the insignificant film of our infinitesimally thin world, as a cat pads through a doorway, whisker, nose, ear, and tail.

0 Comments:

Post a Comment

<< Home