Special Families of Polynomials

Contents

Orthogonal Polynomials

ChebyshevFirst(n) : RngIntElt -> RngUPolElt
ChebyshevT(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the Chebyshev polynomial of the first kind Tn(x), where Tn(x) is defined by Tn(x) = cos n θ with x = cos θ.
ChebyshevSecond(n) : RngIntElt -> RngUPolElt
ChebyshevU(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the Chebyshev polynomial of the second kind, Un(x), of degree n - 1. The polynomial is defined by Un(x) = ((1) /(n)) Tn ' (x) = ((sin n θ) /(sin θ)) where x = cos θ.

LegendrePolynomial(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the Legendre polynomial Pn(x) of degree n, where Pn(x) is defined by eqalign(P0(x) &= 1, P1(x) = x,
Pn(x) &= (1 /(n)) ((2n - 1) x Pn - 1(x) - (n - 1) Pn - 2(x)).)
LaguerrePolynomial(n) : RngIntElt -> RngUPolElt
LaguerrePolynomial(n, m) : RngIntElt, RngElt -> RngUPolElt
Given a positive integer n, this function constructs the Laguerre polynomial Lnm(x) of degree n with parameter m. If m is omitted, it is assumed to be zero if it is not specified. The polynomial satisfies the recurrence relation eqalign(L0(x) &= 1, L1(x) = 1 + m - x,
Ln(x) &= (1 /n) (((2n + m - 1) - x) Ln - 1m(x) - (n - 1 + m) Ln - 2m(x)).)
HermitePolynomial(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the Hermite polynomial Hn(x) of degree n, where Hn(x) is defined by eqalign(H0(x) &= 1, H1(x) = 2x,
Hn(x) &= 2x Hn - 1(x) - 2n Hn - 2(x).)
GegenbauerPolynomial(n, m) : RngIntElt, RngElt ->RngUPolElt
Given a positive integer n and an integer m, this function constructs the Gegenbauer polynomial Cnm(x) of degree n with parameter m, where Cnm(x) is defined by eqalign(C0m(x) &= 1, C1m(x) = 2 m x,
Cnm(x) &= (1 /n)(2(n - 1 + m) x Cn - 1m(x) - (n + 2m - 2) Cn - 2m(x)).)

Permutation Polynomials

DicksonFirst(n, a) : RngIntElt, RngElt -> RngUPolElt
Given a positive integer n, this function constructs the Dickson polynomial of the first kind Dn (x, a) of degree n, where Dn (x, a) is defined by Dn(x, a) = ∑i=0⌊n/2 ⌋ (n /(n - i)) ((n - i) choose i) ( - a)i xn - 2i.

DicksonSecond(n, a) : RngIntElt, RngElt -> RngUPolElt
Given a positive integer n, this function constructs the Dickson polynomial of the second kind En (x, a) of degree n, where En (x, a) is defined by En(x, a) = ∑i=0⌊n/2 ⌋ ((n - i) choose (i)) ( - a)i xn - 2i.

The Bernoulli Polynomial

BernoulliPolynomial(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the n-th Bernoulli polynomial.

Swinnerton-Dyer Polynomials

SwinnertonDyerPolynomial(n) : RngIntElt -> RngUPolElt
Given a positive integer n, this function constructs the n-th Swinnerton-Dyer polynomial, which is defined to be ∏(x ∓ Sqrt(2) ∓ Sqrt(3) ∓ Sqrt(5) ∓ ... ∓ Sqrt(pn)), where pi is the i-th prime and the product runs over all 2n possible combinations of + and - signs. This polynomial lies in Z[x], has degree 2n, and is irreducible over Z.

See Example H24E7 above which explains more about this class of polynomials, and see also Example H43E2 in the chapter on algebraically closed fields to see how these polynomials are constructed and also for a generalization.

V2.28, 13 July 2023