FractalPark
ExoticMedium

Inverted Lambda

A hybrid map that adds a rational quadratic term to the complex logistic recurrence, bringing movable poles into the orbit.

Open in Explorer
The Inverted Lambda fractal with dark lobes split by bright fault lines and knot-like structures
The Inverted Lambda parameter plane: logistic lobes interrupted by the rational correction, with seams and abrupt scale changes.

Overview

Inverted Lambda begins with the Lambda fractal’s logistic recurrence and adds a rational correction. The first term, c·z(1−z), is the standard complex logistic map. The second, 0.18/(z² + c), is reciprocal and quadratic; when its denominator approaches zero, it can hurl the orbit to very large values.

That fraction changes the rules. The plain logistic map is a polynomial, smooth everywhere; Inverted Lambda is a rational map with movable poles. An orbit can head toward infinity through unbounded growth, or by wandering too close to the divisor. The parent’s round lobes remain, but jagged seams, knot-like tangles, and sudden scale changes cut through them.

The 0.18 is fixed, not another parameter. It keeps the polynomial and rational contributions both active within a moderate number of iterations.

The Mathematics

Lambda-reciprocal iteration

z(n+1) = c z(n)(1 - z(n)) + 0.18 / (z(n)^2 + c)

Every step combines two contributions. First comes c·z(1−z), the quadratic logistic step behind the Lambda parameter set. Then comes a rational correction with fixed numerator 0.18 and denominator z² + c. A large denominator makes that correction small, so the map nearly follows the pure logistic version. Near z² + c = 0, it surges and may send the orbit far away.

Take c = 1 + i and start at z₀ = 0. The first term gives 1 × 0 × 1 = 0. The second term: 0.18 / (0 + (1+i)) = 0.18/(1+i) = 0.09 − 0.09i. So z₁ ≈ 0.09 − 0.09i: a small nudge away from the logistic baseline. On later steps the rational term keeps steering, creating paths unavailable to the pure logistic family. The denominator z² + c marks the poles—near-singular values—and their positions move with c.

History

Inverted Lambda is a hybrid construction joining two well-studied complex-dynamics families. Its logistic base comes from the lambda fractal tradition studied by Mandelbrot (1980). Adding a reciprocal quadratic term to a polynomial map relates to singular perturbation, which Curt McMullen explored in the late 1980s for rational maps zⁿ + λ/zⁿ.

This particular pairing—a logistic map and a reciprocal quadratic with a fixed constant numerator—appears to be a novel fractal-rendering formulation. It does not trace to one historical paper; it draws on ideas developed across decades of complex-dynamics research. “Inverted Lambda” describes the construction rather than a term from the research literature.

Visual Characteristics

The parameter plane keeps the logistic family’s rounded lobes, but sharp seams, dense knots, and patches where color suddenly deepens or brightens interrupt them. Near a pole, an orbit makes a large jump, and the escape-time coloring records that break.

It can resemble a smooth surface cracked from within. Far from the poles, the parent Lambda structure is still legible; the rational correction draws angular, crystalline detail across it.

Remix and Examples

Start from the canonical Document

Open the same approved formula state used by this guide, then change the view, coloring, transforms, or animation in the interactive Explorer.

Frequently Asked Questions

What is inverted in this formula?

“Inverted” names the reciprocal term added to the logistic recurrence. It is not a geometric flip of the image or a reflection of the parameter plane. The reciprocal quadratic term 1/(z² + c) is the inversion meant here.

Where can poles occur?

A pole occurs wherever the denominator z² + c is zero — that is, when z = ±√(−c). Since c is free, pole locations depend on the parameter being explored. An evolving orbit may pass close to one, making the rational term spike and the trajectory jump far away.

References

Source walkthrough

  1. frm-v1:5aa4f9b2c35d3bded213756bb80da01f95fef7ee766779a7f02090a1116a0e9a:init/0

    This cited initialization node performs only: if ismand: z = 0; otherwise z = pixel.

  2. frm-v1:5aa4f9b2c35d3bded213756bb80da01f95fef7ee766779a7f02090a1116a0e9a:loop/0

    This cited first loop node performs only: oneMinusZ = (1, 0) - z.

  3. frm-v1:5aa4f9b2c35d3bded213756bb80da01f95fef7ee766779a7f02090a1116a0e9a:bailout

    This cited bailout node tests only: |z| <= 256.

Syntax features

initialization-flow

The initialization annotation isolates if ismand: z = 0; otherwise z = pixel rather than a later initialization statement. This is specific to invertedLambda.

iteration-flow

The iteration annotation isolates the first loop assignment oneMinusZ = (1, 0) - z; invertedLambda first forms oneMinusZ before constructing the lambda term. This is specific to invertedLambda.

bailout-test

The termination annotation identifies the exact continuation comparison |z| <= 256. This is specific to invertedLambda.

Parameter experiment

Steps

  1. Render invertedLambda with the pinned parameter-plane baseline: center (-0.5, 0), zoom 0.4, rotation 0, and 96 iterations.
  2. Keep center (-0.5, 0), zoom 0.4, rotation 0, and 96 iterations fixed except for iterations, render once at 48 iterations, and compare it with the 96-iteration baseline.

What to observe

Record whether the 48- versus 96-iteration comparison changes anything, and note the source limit |z| <= 256. This is the invertedLambda comparison.

Exercise

For invertedLambda, use the three annotations to distinguish the single-node operations if ismand: z = 0; otherwise z = pixel, oneMinusZ = (1, 0) - z, and |z| <= 256; explain why no neighboring statement belongs to the loop annotation.

Completion check

Name all 3 annotation IDs, then state exactly that the cited loop node is oneMinusZ = (1, 0) - z and the cited bailout node is |z| <= 256. This completes the invertedLambda reading.

Sources and rights

Grounded in runtime source revision 5aa4f9b2c35d3bded213756bb80da01f95fef7ee766779a7f02090a1116a0e9a and the publication decision for c6b5dcf4-cef5-5630-b3f6-a68b92ae75ee.

rightsStatus is project-owned; implementationBasis is project-owned; publicationDecision is publish; decisionReason is publish-project-owned-native-recipe. These records describe this project decision only and do not assert broader rights in any third-party original.

Formula Record

invertedLambda

This canonical FractalPark implementation is published and runnable.

Deterministic preview of invertedLambda

Canonical source

Language
frm-like/1
Standard library
1
Profile mode
parameter-plane
Profile center
-0.5, 0
Profile zoom
0.4
Profile iterations
96
Profile evidence
mechanical

Parameters

No declared parameters

Canonical source

This verified canonical revision is read-only. Remix creates a separate editable fork.

Loading canonical source…

Source and implementation

Formula ID
c6b5dcf4-cef5-5630-b3f6-a68b92ae75ee
Canonical name
invertedLambda
Original name
invertedLambda
Historical source
FractalPark
Current implementation
Project-owned

This is a FractalPark project-owned implementation. The linked file is the pinned canonical Definition.

Rights or attribution concern?

Send the Formula ID and supporting evidence. The maintainer can hold or withdraw the implementation while the claim is reviewed. contact@fractalpark.com