Difference between revisions of "ApCoCoA-1:BB.ASneighbors"

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     </description>
 
     </description>
 
     <see>BB.NDneighbors</see>
 
     <see>BB.NDneighbors</see>
     <key>kreuzer</key>
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     <key>ASneighbors</key>
     <key>bb.asneighbors</key>
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     <key>BB.ASneighbors</key>
     <key>borderbasis.asneighbors</key>
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     <key>borderbasis.ASneighbors</key>
 
     <wiki-category>Package_borderbasis</wiki-category>
 
     <wiki-category>Package_borderbasis</wiki-category>
 
</command>
 
</command>

Revision as of 18:48, 22 April 2009

BB.ASneighbors

Compute 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 <formula>[i,j,k,l]</formula> such that <formula>x_k * b_i = x_l * b_j</formula>.

  • @param OO A list of terms representing an order ideal.

  • @return A list of across-the-street neighbors of OO.

Example

Use Q[x,y,z];
BB.ASneighbors([1,x]);
[[1, 2, 2, 3], [3, 4, 2, 3], [3, 5, 1, 3], [4, 5, 1, 2]]
-------------------------------

BB.NDneighbors