内维尔Θ函数(Neville Theta functions)共有四个,定义如下:
N e v i l l e C ( z , m ) = ( 2 ) ∗ q ( m ) 1 / 4 ∗ ( ∑ k = 0 ∞ ( q ( m ) ( k ∗ ( k + 1 ) ) ∗ c o s ( ( 1 / 2 ) ∗ ( 2 ∗ k + 1 ) ∗ π ∗ z / K ( m ) ) ) ) ( K ( m ) ) ∗ m 1 / 4 {\displaystyle NevilleC(z,m)={\frac {{\sqrt {(}}2)*q(m)^{1/4}*(\sum _{k=0}^{\infty }(q(m)^{(}k*(k+1))*cos((1/2)*(2*k+1)*\pi *z/K(m))))}{{\sqrt {(}}K(m))*m^{1/4}}}} N e v i l l e T h e t a C ( z , m ) = ( 2 ∗ π ) ∗ q ( m ) 1 / 4 ∗ ( ∑ k = 0 ∞ ( q ( m ) k ∗ ( k + 1 ) ∗ c o s ( ( 1 / 2 ) ∗ ( 2 ∗ k + 1 ) ∗ π ∗ z / K ( m ) ) ) ) ( K ( m ) ) ∗ m 1 / 4 {\displaystyle NevilleThetaC(z,m)={\frac {{\sqrt {(}}2*\pi )*q(m)^{1/4}*(\sum _{k=0}^{\infty }(q(m)^{k*(k+1)}*cos((1/2)*(2*k+1)*\pi *z/K(m))))}{{\sqrt {(}}K(m))*m^{1/4}}}} N e v i l l e T h e t a D ( z , m ) = ( ( 1 / 2 ) ∗ π ) ∗ ( 1 + 2 ∗ ( ∑ k = 1 ∞ ( q ( m ) ( k 2 ) ∗ c o s ( k ∗ π ∗ z / K ( m ) ) ) ) ) ( K ( m ) ) {\displaystyle NevilleThetaD(z,m)={\frac {{\sqrt {(}}(1/2)*\pi )*(1+2*(\sum _{k=1}^{\infty }(q(m)^{(}k^{2})*cos(k*\pi *z/K(m)))))}{{\sqrt {(}}K(m))}}} N e v i l l e T h e t a N ( z , m ) = ( π ) ∗ ( 1 + 2 ∗ ( ∑ k = 1 ∞ ( ( − 1 ) k ∗ q ( m ) k 2 ∗ c o s ( k ∗ π ∗ z / K ( m ) ) ) ) ) ( 2 ) ∗ ( 1 − m ) ( 1 / 4 ) ∗ K ( m ) {\displaystyle NevilleThetaN(z,m)={\frac {{\sqrt {(}}\pi )*(1+2*(\sum _{k=1}^{\infty }((-1)^{k}*q(m)^{k^{2}}*cos(k*\pi *z/K(m)))))}{{\sqrt {(}}2)*(1-m)^{(}1/4)*{\sqrt {K(m)}}}}}
其中
尼维尔Θ函数也可以通过雅可比Θ函数的傅里叶级数来定义,并使得尼维尔Θ函数可以进一步被用于定义相对应的雅可比椭圆函数。
这种定义涉及到第一类完全椭圆积分。
利用Maple,将z=2.5,m=3 代人上列公式,即得: 与wolfram math结果相当: