CASA Function: neighborhoodTree
Checks whether a given object is a neighborhood tree.
- b := `type/neighborhoodTree`(l)
- b := type(l,neighborhoodTree)
- l : list(list)
- b : boolean
- Either true or false, depending on whether the list of lists is a neighborhood tree or not.
- This function checks whether a given object is a neighborhood tree or not.
- A neighborhood tree is defined recursively. First of all, the empty list is a neighborhood tree. A list l of lists is a neighborhood tree if, first of al, the lists l[i] in l contain six elements. The first element is a nonnegative integer; the second, third and fourth elements are coordinates of a point in a projective plane. The fifth element is a set of transformations. The sixth element l[i] again is a neighborhood tree. And if, secondly, this definition ends; i.e. for every 1 <= i <= nops(l) we have a certain k[i] such that l[i].. =  with k[i] levels.
> A := mkImplAlgSet([y^6-x^3+x^4+x^6],[x,y]);
> G := neighbGraph(A);