ModularLambda

ModularLambda[τ]

gives the modular lambda elliptic function TemplateBox[{tau}, ModularLambda].

Details

  • Mathematical function, suitable for both symbolic and numerical manipulation.
  • ModularLambda is defined only in the upper half of the complex plane. It is not defined for real .
  • The argument is the ratio of Weierstrass halfperiods .
  • ModularLambda gives the parameter for elliptic functions in terms of according to m=TemplateBox[{tau}, ModularLambda].
  • ModularLambda is related to EllipticTheta by TemplateBox[{tau}, ModularLambda]=TemplateBox[{2, 0, q}, EllipticTheta]^4/TemplateBox[{3, 0, q}, EllipticTheta]^4 where the nome is given by .
  • is invariant under any combination of the modular transformations and . »
  • For certain special arguments, ModularLambda automatically evaluates to exact values.
  • ModularLambda can be evaluated to arbitrary numerical precision.
  • ModularLambda can be used with CenteredInterval objects. »
  • ModularLambda automatically threads over lists. »

Examples

open allclose all

Basic Examples  (3)

Evaluate numerically:

Plot over a subset of the reals:

Series expansion at the origin:

Scope  (23)

Numerical Evaluation  (5)

Evaluate numerically:

Evaluate to high precision:

The precision of the output tracks the precision of the input:

Evaluate efficiently at high precision:

Compute the elementwise values of an array using automatic threading:

Or compute the matrix ModularLambda function using MatrixFunction:

ModularLambda can be used with CenteredInterval objects:

Specific Values  (2)

Value at a fixed point:

Find the first positive minimum of ModularLambda[x+I]:

Visualization  (3)

Plot the real part of ModularLambda:

Plot the absolute value of ModularLambda:

Plot the real part of ModularLambda function:

Plot the imaginary part of ModularLambda function:

Function Properties  (9)

ModularLambda is defined in the upper half-plane:

ModularLambda is a periodic function:

ModularLambda threads elementwise over lists:

ModularLambda is an analytic function on its domain:

Therefore it has neither singularities nor discontinuities there:

Re(TemplateBox[{{x, +, ⅈ}}, ModularLambda]) is neither nondecreasing nor nonincreasing:

Re(TemplateBox[{{x, +, ⅈ}}, ModularLambda]) is not surjective:

Re(TemplateBox[{{x, +, ⅈ}}, ModularLambda]) is neither non-negative nor non-positive:

Re(TemplateBox[{{x, +, ⅈ}}, ModularLambda]) is neither convex nor concave:

TraditionalForm formatting:

Differentiation  (2)

First derivative with respect to z:

Higher derivatives with respect to z:

Plot the higher derivatives with respect to z:

Series Expansions  (2)

Find the Taylor expansion using Series:

Plots of the first three approximations around :

Taylor expansion at a generic point:

Applications  (4)

Some modular properties of ModularLambda are automatically applied:

Verify a more complicated identity numerically:

ModularLambda is a modular function. Make an ansatz for a modular equation:

Form an overdetermined system of equations and solve it:

This is the modular equation of order 2:

Solution of the DarbouxHalphen system:

Check:

Plot the real part in the complex plane:

Properties & Relations  (2)

Find derivatives:

Find a numerical root:

Possible Issues  (2)

Machine-precision input is insufficient to give a correct answer:

With exact input, the answer is correct:

ModularLambda remains unevaluated outside of its domain of analyticity:

Wolfram Research (1996), ModularLambda, Wolfram Language function, https://reference.wolfram.com/language/ref/ModularLambda.html (updated 2021).

Text

Wolfram Research (1996), ModularLambda, Wolfram Language function, https://reference.wolfram.com/language/ref/ModularLambda.html (updated 2021).

CMS

Wolfram Language. 1996. "ModularLambda." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2021. https://reference.wolfram.com/language/ref/ModularLambda.html.

APA

Wolfram Language. (1996). ModularLambda. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ModularLambda.html

BibTeX

@misc{reference.wolfram_2024_modularlambda, author="Wolfram Research", title="{ModularLambda}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/ModularLambda.html}", note=[Accessed: 07-October-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_modularlambda, organization={Wolfram Research}, title={ModularLambda}, year={2021}, url={https://reference.wolfram.com/language/ref/ModularLambda.html}, note=[Accessed: 07-October-2024 ]}