Function: mfTheta
Section: modular_forms
C-Name: mfTheta
Prototype: DG
Help: mfTheta({psi=1}): the unary theta function corresponding to the primitive
Dirichlet character psi, hence of weight 1/2 if psi is even, of weight 3/2
if psi is odd.
Doc: the unary theta function corresponding to the primitive Dirichlet
character $\psi$, hence of weight $1/2$ if $\psi$ is even, of weight $3/2$
if $\psi$ is odd.
\bprog
? Ser(mfcoefs(mfTheta(),30))
%1 = 1 + 2*x + 2*x^4 + 2*x^9 + 2*x^16 + 2*x^25 + O(x^31)
? Ser(mfcoefs(mfTheta(8),30))
%2 = 2*x - 2*x^9 - 2*x^25 + O(x^31)
? Ser(mfcoefs(mfTheta(-8),30))
%3 = 2*x + 6*x^9 - 10*x^25 + O(x^31)
@eprog