Package sagbi/SB.GetSAGBI

From ApCoCoAWiki
This article is about a function from ApCoCoA-2.


This function returns the reduced SAGBI basis of a given subalgebra.


SB.GetSAGBI(ref S: TAGGED("$apcocoa/sagbi.Subalgebra"): LIST of POLY


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


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

HowTo:Term Orderings

HowTo:Call by Reference

Package sagbi/SB.SAGBI

Package sagbi/SB.Subalgebra

Package sagbi/SB.GetID

Package sagbi/SB.GetRing

Package sagbi/SB.GetGens

Package sagbi/SB.GetCoeffRing

Package sagbi/SB.GetTruncSAGBI

Package sagbi/SB.GetTruncDeg

Package sagbi/SB.GetLTSA

Package sagbi/SB.GetInDeg

Package sagbi/SB.GetHS