Given a square of size n by m, how many ways could we choose sites, such that all the sites are connected?
By connected,"connected" we mean "connected" by adjacent sites. We will illustrate by example, say, we choose all the "1" sites and all the "0" sites are not chosen. Then
00000
00100
00100
00110
00000
is connected and
00000
00100
00010
00010
00000
is not connected.
A more difficult question would be, how many ways could we choose sites. Such that there are at most 2 connected "island"(or component):
For example:
00001
00001
00110
00100
has 2 connected component and
00001
00100
00010
00000
has 3 connected component.
The ultimate question is, given a cube size of n by m by k, how many ways could we choose sites, such that there are at most j connected components?
I face this question in my research in designing algorithm for material science. Thank you:)