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| | Elliptic and Modular Functions |
 | | Given a lattice L = [a, b] in the complex plane, this function returns the value of the elliptic j-invariant of L. This is the j-invariant of tau where tau = a/b or tau = b / a, whichever is in the upper half complex plane. |
 | | Defined this way, theta satisfies theta(q, - z)= - theta(q, z), it is periodic with period 2pi in the second variable: theta(q, z + 2pi)= theta(q, z), and its zeroes are of the form m_1pi + m_2(log x/i) for any integers m_1, m_2. |
 | | This is a modular function of weight 0 whose Fourier expansion starts with j(s)=e^(-2pi i s) + 744e(2pi i s) + 196884e(2pi i s) +... |
| www.math.wisc.edu /help/magma/text467.html (1285 words) |
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