Search NKS | Online
481 - 490 of 630 for Random
The local positions of stars are generally assumed to be random. 88 constellations are usually named—quite a few presumably already identified by the Babylonians and Sumerians around 2000 BC.
Density of difficult problems
There are arguments that in an asymptotic sense most instances chosen at random of problems like limited-size PCP or tiling will be difficult to solve.
[Networks generated by] random replacements
As indicated in the note above, applying the second rule (T1, shown as (b) on page 511 ) at an appropriate sequence of positions can transform one planar network into any other with the same number of nodes. The pictures below show what happens if this rule is repeatedly applied at random positions in a network.
For 3Ă—3 templates with two colors extensive randomized searches have failed to discover examples where non-repetitive patterns are forced to occur.
With completely random initial conditions, there are great fluctuations, but a typical period is around 2 n/3 .
With this setup my experience is that both repetitive and random sequences tend to seem quite monotonous and dull.
At least up to n = 10 6 terms, it increases roughly like 13.5n , but as shown below the fluctuations seem random.
Percolation
A simple example of a phase transition studied extensively since the 1950s involves taking a square lattice and filling in at random a certain density of black cells.
The result of this is that in most situations patterns of shocks generated have a fairly simple geometrical structure, with none of the randomness of turbulence.
If one starts with completely random initial conditions then class 2 and class 3 behavior are often seen.