Difference between revisions of "ApCoCoA-1:CharP.GBasisModSquares"
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<command> | <command> | ||
<title>Char2.GBasisModSquares</title> | <title>Char2.GBasisModSquares</title> | ||
| − | <short_description>Computing a Groebner Basis of a given ideal intersected with x^2-x for all indeterminates x.</short_description> | + | <short_description>Computing a Groebner Basis of a given ideal intersected with <tt>x^2-x</tt> for all indeterminates <tt>x</tt>.</short_description> |
<syntax> | <syntax> | ||
Char2.GBasisModSquares(Ideal:IDEAL):LIST | Char2.GBasisModSquares(Ideal:IDEAL):LIST | ||
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<em>Please note:</em> The function(s) explained on this page is/are using the <em>ApCoCoAServer</em>. You will have to start the ApCoCoAServer in order to use it/them. | <em>Please note:</em> The function(s) explained on this page is/are using the <em>ApCoCoAServer</em>. You will have to start the ApCoCoAServer in order to use it/them. | ||
<par/> | <par/> | ||
| − | This function returns the reduced Groebner basis for the given ideal intersected with the ideal generated by x^2-x for all indeterminates. If x^2-x for | + | This function returns the reduced Groebner basis for the given ideal intersected with the ideal generated by <tt>x^2-x</tt> for all indeterminates. If <tt>x^2-x</tt> for all indeterminates is in the ideal (e.g. the set of zeros is a subset of <tt>{0,1}^n</tt>) this method should produce the Groebner Basis much faster! |
| − | all indeterminates is in the ideal (e.g. the set of zeros is a subset of {0,1}^n) this method should produce the Groebner Basis much faster! | + | Please be aware, that this is much more efficient if the term ordering is Lex, DegLex or DegRevLex. Otherwise, first a DegRevLex Groebner Basis is computed and then transformed with the <ref>FGLM.FGLM</ref>-algorithm. |
| − | Please be aware, that this is much more efficient if the term ordering is Lex, DegLex or DegRevLex. Otherwise, first a DegRevLex Groebner Basis is computed and then transformed with the FGLM-algorithm. | ||
<itemize> | <itemize> | ||
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<item>@return The reduced Groebner Basis of the given ideal.</item> | <item>@return The reduced Groebner Basis of the given ideal.</item> | ||
</itemize> | </itemize> | ||
| + | |||
| + | <example> | ||
| + | Use R::=QQ[x,y,z]; | ||
| + | I:=Ideal(x-y^2,x^2+xy,y^3); | ||
| + | GBasis(I); | ||
| + | |||
| + | [x^2 + xy, -y^2 + x, -xy] | ||
| + | ------------------------------- | ||
| + | Use Z::=ZZ[x,y,z]; | ||
| + | -- WARNING: Coeffs are not in a field | ||
| + | -- GBasis-related computations could fail to terminate or be wrong | ||
| + | |||
| + | ------------------------------- | ||
| + | I:=Ideal(x-y^2,x^2+xy,y^3); | ||
| + | Char2.GBasisModSquares(I); | ||
| + | -- WARNING: Coeffs are not in a field | ||
| + | -- GBasis-related computations could fail to terminate or be wrong | ||
| + | -- CoCoAServer: computing Cpu Time = 0 | ||
| + | ------------------------------- | ||
| + | [y, x] | ||
| + | ------------------------------- | ||
| + | </example> | ||
| + | |||
</description> | </description> | ||
Revision as of 07:55, 14 July 2009
Char2.GBasisModSquares
Computing a Groebner Basis of a given ideal intersected with x^2-x for all indeterminates x.
Syntax
Char2.GBasisModSquares(Ideal:IDEAL):LIST
Description
Please note: The function(s) explained on this page is/are using the ApCoCoAServer. You will have to start the ApCoCoAServer in order to use it/them.
This function returns the reduced Groebner basis for the given ideal intersected with the ideal generated by x^2-x for all indeterminates. If x^2-x for all indeterminates is in the ideal (e.g. the set of zeros is a subset of {0,1}^n) this method should produce the Groebner Basis much faster!
Please be aware, that this is much more efficient if the term ordering is Lex, DegLex or DegRevLex. Otherwise, first a DegRevLex Groebner Basis is computed and then transformed with the FGLM.FGLM-algorithm.
@param Ideal An Ideal.
@return The reduced Groebner Basis of the given ideal.
Example
Use R::=QQ[x,y,z]; I:=Ideal(x-y^2,x^2+xy,y^3); GBasis(I); [x^2 + xy, -y^2 + x, -xy] ------------------------------- Use Z::=ZZ[x,y,z]; -- WARNING: Coeffs are not in a field -- GBasis-related computations could fail to terminate or be wrong ------------------------------- I:=Ideal(x-y^2,x^2+xy,y^3); Char2.GBasisModSquares(I); -- WARNING: Coeffs are not in a field -- GBasis-related computations could fail to terminate or be wrong -- CoCoAServer: computing Cpu Time = 0 ------------------------------- [y, x] -------------------------------
See also
Introduction to Groebner Basis in CoCoA
Representation of finite fields
