Difference between revisions of "ApCoCoA-1:BB.ASneighbors"
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Revision as of 12:38, 28 April 2009
BB.ASneighbors
Computes a list of across-the-street neighbors.
Syntax
BB.ASneighbors(OO:LIST):LIST
Description
Computes the list of across-the-street neighbors in the border of the order ideal OO. The input is a list OO of terms that specify an order ideal. The output is a list of quadruples [i,j,k,l] such that x_k * b_i = x_l * b_j.
@param OO A list of terms representing an order ideal.
@return A list of across-the-street neighbors of OO.
Example
Use QQ[x,y,z]; BB.ASneighbors([1,x]); [[1, 2, 2, 3], [3, 4, 2, 3], [3, 5, 1, 3], [4, 5, 1, 2]] -------------------------------
