Package borderbasis
From ApCoCoAWiki
| This article is about a function from ApCoCoA-2. If you are looking for the ApCoCoA-1 version of it, see Category:ApCoCoA-1:Package borderbasis. |
This page describes the borderbasis package. The package contains various functions for computing with border bases of order ideals in a polynomial ring P=K[x_1,...,x_n] over a field K. We refer the book [M. Kreuzer and L. Robbiano, Computational Commutative Algebra 2, Springer-Verlag, Berlin, 2005] for more details about border bases. For a complete list of functions, see also Category:Package borderbasis.
The Global Alias of the package is BB.
List of the main functions
IsOrderIdeal(OO): checks whether OO is an order ideal.
input: OO a non-empty set of terms in K[x[1..N]]
output: boolean value for checking OO being an order ideal
Border(OO): computes the border of an order ideal.
input: list of terms
output: list of terms in ascending order
Box(P,D): computes the 'box' order ideal of type D=[D1,..,DN].
input: list of integers D of length NumIndets(P), P=K[x[1..N]]
output: list of terms (sorted w.r.t. current TO)
BBasisForOI(F,OO): computes the border basis of the ideal I=<F> with respect to the order ideal OO,
gives an error messages if no border basis exists, uses the O_sigma(I) border basis and the BB transformation.
input: list of poly F, list of terms OO
output: list of poly
BorderDivAlg(P,F,OO,Prebasis): applies the Border Division Algorithm w.r.t. the order ideal OO and the border prebasis
Prebasis to the polynomial F and returns a record with fields
Quotients and Remainder where Remainder is the normal OO-remainder of F.
input: poly F, list of terms OO, list of poly Prebasis
output: record with two fields Quotients and Remainder
List of support functions
LinPart(P,F): computes the homogeneous part of degree 1.
input: P = Poly ring, F = Poly or list of Poly
output: Poly or list of Poly
RLF(P,F): RLF of a polynomial returns its linear form which vanishes at the origin, independently of the grading.
RLF of a list of poly or an ideal I returns the reduced GB of the ideal generatd by the RLF of the Gens of I.
input: P = Poly ring, F = Poly or list of Poly or ideal
output: Poly or list of Poly
CoeffPoly(P,T,F,X): find the 'multivariate' coefficient of a term in a poly.
input: P = Poly ring, T term, F poly, X set of indets
output: polynomial coefficent of T in F such that no coefficient is in <X>
DF(P,F): degree form of a polynomial F.
input: P = Poly ring, F poly
output: Poly
Ccolumn(BBS, J): contructs the column (C[1,J],...,C[Mu,J])^{tr}.
input: BBS is the bb poly ring, J In 1..Nu
output: a (Mu x 1)-matrix of indets
HomCcolumn(BBS,J,OO): contructs the 'homogeneous' column (D[1,J],...,D[Mu,J])^{tr}
where D[I,J]=C[I,J] if Deg(t_i)=Deg(b_j) and D[I,J]=0 otherwise.
input: BBS is the bb poly ring, J In 1..Nu, OO order ideal
output: a (Mu x 1)-matrix of indets
IsListOfTerms(L): checks if a list is a list of terms.
input: non-empty LIST of POLY
output: TRUE if L is a list of terms, FALSE otherwise
ArrDeg(BBS, OO, opt L): computes the triple [indet, arrow-degree, arrow] of the indeterminates in L.
input: BBS is the bb poly ring, L list of indets of BBS, OO order ideal
output: [indet, arrow-degree, arrow]
TotArrDeg(BBS, OO, opt L): computes the triple [indet, Total arrow-degree, arrow] of the indeterminates in L.
input: BBS is the bb poly ring, L list of indets of BBS, OO order ideal
output: [indet, Total arrow-degree, arrow]
NonNegTotArrDeg(BBS, OO, opt L): computes the indets with non-negative total-arrow-degree.
input: BBS is the bb poly ring, L list of indets of BBS, OO order ideal
output: list of indets";
PositiveArrow(BBS, OO, opt L): computes the indets with positive total-arrow-degree.
input: BBS is the bb poly ring, L list of indets of BBS, OO order ideal
output: list of indets
ZeroTotArrDeg(BBS, OO, opt L): computes the indets with zero total-arrow-degree.
input: BBS is the bb poly ring, L list of indets of BBS, OO order ideal
output: list of indets
InteriorCij(BBS,OO): computes the indeterminates in BBS associated to the interior terms in OO
input: OO order ideal, BBS is the bb poly ring
output: list of interior indets
Example for computations
- See also: BB.Border
