>>1 Bernstein–Sato polynomialか
(参考)
https://en.wikipedia.org/wiki/Bernstein%E2%80%93Sato_polynomial Bernstein–Sato polynomial
In mathematics, the Bernstein–Sato polynomial is a polynomial related to differential operators, introduced independently by Joseph Bernstein (1971) and Mikio Sato and Takuro Shintani (1972, 1974), Sato (1990). It is also known as the b-function, the b-polynomial, and the Bernstein polynomial, though it is not related to the Bernstein polynomials used in approximation theory. It has applications to singularity theory, monodromy theory, and quantum field theory.
Severino Coutinho (1995) gives an elementary introduction, while Armand Borel (1987) and Masaki Kashiwara (2003) give more advanced accounts.
Definition and properties
Definition and properties
If f(x) is a polynomial in several variables, then there is a non-zero polynomial
b(s) and a differential operator
P(s) with polynomial coefficients such that
略
The Bernstein–Sato polynomial is the monic polynomial of smallest degree amongst such polynomials
b(s). Its existence can be shown using the notion of holonomic D-modules.
Kashiwara (1976) proved that all roots of the Bernstein–Sato polynomial are negative rational numbers.
Nero Budur, Mircea Mustață, and Morihiko Saito (2006) generalized the Bernstein–Sato polynomial to arbitrary varieties.
Note, that the Bernstein–Sato polynomial can be computed algorithmically. However, such computations are hard in general. There are implementations of related algorithms in computer algebra systems RISA/Asir, Macaulay2, and SINGULAR.
Applications
・The Malgrange–Ehrenpreis theorem states that every differential operator with constant coefficients has a Green's function. By taking Fourier transforms this follows from the fact that every polynomial has a distributional inverse, which is proved in t
ブックマークへ
