Golden Projective Derivative
Abstract
The golden Mobius derivative equals its projective multiplier.
Theorem 1.1 (Golden Mobius Has Deriv At).
Proof. Machine-checked in Lean as D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.golden_mobius_hasDerivAt (✓ std3). ∎
Source. Repository-derived.
Commentary.
Ordinary differentiation gives the same multiplier as exact projective linearization.
The declaration keeps its parameters and hypotheses explicit; the result makes no converse or broader existence claim beyond that scope.
Theorem 1.2 (Deriv Golden Mobius At Golden).
Proof. Machine-checked in Lean as D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.deriv_golden_mobius_at_golden (✓ std3). ∎
Source. Repository-derived.
Commentary.
Evaluation of deriv at the golden fixed point.
The declaration keeps its parameters and hypotheses explicit; the result makes no converse or broader existence claim beyond that scope.
Theorem 1.3 (Abs Golden Projective Multiplier).
Proof. Machine-checked in Lean as D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.abs_golden_projective_multiplier (✓ std3). ∎
Source. Repository-derived.
Commentary.
The projective multiplier has the expected positive magnitude.
The declaration keeps its parameters and hypotheses explicit; the result makes no converse or broader existence claim beyond that scope.
Theorem 1.4 (Abs Golden Projective Multiplier lt One).
Proof. Machine-checked in Lean as D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.abs_golden_projective_multiplier_lt_one (✓ std3). ∎
Source. Repository-derived.
Commentary.
The completion derivative is a strict contraction in projective coordinates.
The declaration keeps its parameters and hypotheses explicit; the result makes no converse or broader existence claim beyond that scope.
Theorem 1.5 (Linearized Golden Has Deriv At Zero).
Proof. Machine-checked in Lean as D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.linearized_golden_hasDerivAt_zero (✓ std3). ∎
Source. Repository-derived.
Commentary.
Multiplication by the golden multiplier has that derivative at zero.
The declaration keeps its parameters and hypotheses explicit; the result makes no converse or broader existence claim beyond that scope.
References
- Truth anchor:
D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.abs_golden_projective_multiplier - Truth anchor:
D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.abs_golden_projective_multiplier_lt_one - Truth anchor:
D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.deriv_golden_mobius_at_golden - Truth anchor:
D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.golden_mobius_hasDerivAt - Truth anchor:
D5/S3/CompletionDynamics/GoldenMobius/GoldenProjectiveDerivative.linearized_golden_hasDerivAt_zero - Dependency: D5/S3/CompletionDynamics/GoldenMobius/GoldenCrossRatioLinearization