Modular lambda function: Difference between revisions

Revision as of 18:01, 11 December 2021

Revision as of 18:06, 11 December 2021

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==Relations to other functions==

It is the [[Square (algebra)|square]] of the [[Jacobielliptic modulus]],<ref name=C108>Chandrasekharan (1985) p.108</ref> that is, <math>\lambda(\tau)=k^2(\tau)</math>. In terms of the [[Dedekind eta function]] <math>\eta(\tau)</math> and [[theta function]]s,<ref name=C108/>

:<math> \lambda(\tau) = \Bigg(\frac{\sqrt{2}\,\eta(\tfrac{\tau}{2})\eta^2(2\tau)}{\eta^3(\tau)}\Bigg)^8 = \frac{16}{\left(\frac{\eta(\tau/2)}{\eta(2\tau)}\right)^8 + 16} =\frac{\theta_2^4(\tau)}{\theta_3^4(\tau)} </math>