Simple Relation between the Lowest-Order Element of Ideal 〈G,H〉 and the Last Element of Polynomial Remainder Sequence
Simple Relation between the Lowest-Order Element of Ideal 〈G,H〉 and the Last Element of Polynomial Remainder Sequence
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DOI:
10.1109/synasc.2017.00019
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发表时间:
2017-09
期刊:
影响因子:
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通讯作者:
Tateaki Sasaki;D. Inaba
中科院分区:
文献类型:
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作者:
Tateaki Sasaki;D. Inaba
Let G and H be relatively prime polynomials in K[x,u], where K is a number field and (u) = (u1, . . . , uℓ), with ℓ ≥ 2. Let GB(G,H) be the reduced Gröbner basis of ideal hG,Hi, w.r.t. the elimination order for x. Let Ŝ be the lowest-order element of GB(G,H), and Ã, B ∈ K[x,u] be the cofactors of Ŝ: ÃG+ e BH = Ŝ. Let PRS(G,H) be the polynomial remainder sequence w.r.t. x, with initial polynomials G and H. Let Pk ∈ K[u] be the last element of PRS(G,H), and Ak,Bk ∈ K[x,u] be cofactors of Pk: AkG + BkH = Pk. Ak and Bk satisfy degree conditions: degx(Ak) < degx(H) and degx(Bk) < degx(G), while e à and B in general do not. Computing  and B by reducing the degrees w.r.t. x, of à and B, respectively, and by normalizing Pk suitably, we show that (Pk,Ak,Bk) = c ( Ŝ, Â, B), where (P,A,B) denotes a tuple and c ∈ K. We then present a new method for solving the multivariate Diophantine equation ϕ G + ψH = F for given F ∈ K[x,u] and unknowns φ , ψ ∈ K(u)[x]. Furthermore, we show a new method for solving the ideal-membership problem for 〈G,H〉, without computing any Gröbner basis.