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

From ApCoCoAWiki
(Updated description. (Skaspar))
(Updated examples.)
Line 13: Line 13:
 
</itemize>
 
</itemize>
 
<example>
 
<example>
Use QQ[x,y];
+
Use Q[x,y], DegLex;
BB.BBasisForMP([ [,], [,] ]);
 
  
 +
F := [
 +
[ x^2 + xy - 1/2y^2 - x - 1/2y, xy ],
 +
[ y^3 - y, y^3 ],
 +
[ xy^2 - xy, xy^2 ]
 +
];
 +
 +
BB.BBasisForMP(F);
 +
 +
[[x^2 + xy - 1/2y^2 - x - 1/2y, xy],
 +
[y^3 - y, y^3],
 +
[xy^2 + x^2 - 1/2y^2 - x - 1/2y, xy^2],
 +
[x^3 - x, x^3],
 +
[x^2y - 1/2y^2 - 1/2y, x^2y]]
 +
-------------------------------
 +
</example>
 +
<example>
 +
Use Q[x,y,z], DegLex;
 +
 +
F := [
 +
[ x^2 + xy + y^2 - x - 1, x^2 ],
 +
[ xy + y^2 + z, xy ],
 +
[ -x^2 + yz + z + 1, x^2 ]
 +
];
 +
 +
BB.BBasisForMP(F);
 +
 +
[[x^2 - x - z - 1, x^2],
 +
[xy + z^2 + x + z + 1, xy],
 +
[yz - x, yz],
 +
[y^2 - z^2 - x - 1, y^2],
 +
[x^2z - xz - z^2 - z, x^2z],
 +
[xz^2 + xz - z^2 + 2x + y, xz^2],
 +
[xyz - x - z - 1, xyz],
 +
[z^3 + xz + z^2 + x + 2z + 1, z^3],
 +
[yz^2 - xz, yz^2]]
 
-------------------------------
 
-------------------------------
 
</example>
 
</example>

Revision as of 13:59, 29 September 2009

BB.BBasisForMP

Computes the border basis of a zero-dimensional ideal generated by marked polynomials.

Syntax

BB.BBasisForMP(F:LIST of LIST):LIST of LIST

Description

The input is a list of tuples [P, T] where P is a polynomial and T must be a term of the support of P such that deg(P) = deg(T). This function computes the border basis of the zero-dimensional ideal I generated by the polynomials P with respect to the given term marking. The output is a list of tuples [P, T] denoting a border basis of I where P is a polynomial and T is the term of the support of P such that deg(P) = deg(T) and T is a border term. An error will be raised if the given term marking does not lead to a successful computation.

  • @param F List of tuples [P, T] where P is a polynomial and T must be a term of the support of P such that deg(P) = deg(T). The polynomials P must generate a zero-dimensional ideal.

  • @return A list of tuples [P, T] denoting a border basis of I where P is a polynomial and T is the term of the support of P such that deg(P) = deg(T) and T is a border term.

Example

Use Q[x,y], DegLex;

F := [
[ x^2 + xy - 1/2y^2 - x - 1/2y, xy ],
[ y^3 - y, y^3 ],
[ xy^2 - xy, xy^2 ]
];

BB.BBasisForMP(F);

[[x^2 + xy - 1/2y^2 - x - 1/2y, xy],
 [y^3 - y, y^3],
 [xy^2 + x^2 - 1/2y^2 - x - 1/2y, xy^2],
 [x^3 - x, x^3],
 [x^2y - 1/2y^2 - 1/2y, x^2y]]
-------------------------------

Example

Use Q[x,y,z], DegLex;

F := [
[ x^2 + xy + y^2 - x - 1, x^2 ],
[ xy + y^2 + z, xy ],
[ -x^2 + yz + z + 1, x^2 ]
];

BB.BBasisForMP(F);

[[x^2 - x - z - 1, x^2],
 [xy + z^2 + x + z + 1, xy],
 [yz - x, yz],
 [y^2 - z^2 - x - 1, y^2],
 [x^2z - xz - z^2 - z, x^2z],
 [xz^2 + xz - z^2 + 2x + y, xz^2],
 [xyz - x - z - 1, xyz],
 [z^3 + xz + z^2 + x + 2z + 1, z^3],
 [yz^2 - xz, yz^2]]
-------------------------------

BB.BBasis

BB.BBasisForOI