Package sagbi/SB.GetSAGBI
From ApCoCoAWiki
| This article is about a function from ApCoCoA-2. |
SB.GetSAGBI
This function returns the reduced SAGBI basis of a given subalgebra.
Syntax
SB.GetSAGBI(ref S: TAGGED("$apcocoa/sagbi.Subalgebra"): LIST of POLY
Description
This function takes a subalgebra S as a reference, computes its unique reduced SAGBI basis, returns it and saves it into S if the function wasn't called previously. If the function was called previously on the same subalgebra, then it just returns the reduced SAGBI basis of S. If no finite SAGBI basis is found after 120 seconds, the function stops and returns an error.
@param S A subalgebra
@return The reduced SAGBI basis of S
Example
Use R ::= QQ[x,y]; fs := [x^2*y, x^2 -y^2, x^2*y^2 -y^4, x^2*y^4]; S := SB.Subalgebra(R,fs); PrintLn SB.GetSAGBI(ref S); -- [x^2 -y^2, x^2*y, x^2*y^2 -y^4, y^6, x^2*y^4]
See also
Package sagbi/SB.GetTruncSAGBI
