Apoth3osis
<_RESEARCH/PROJECTS

Dual-Differentiable: DiLL for SKY

VERIFIED0 SORRY5 MENTAT CERTSLean 4 + Mathlib
>_VERIFICATION.SEAL
FORMALLY VERIFIED • LEAN 4 • MACHINE-CHECKED • APOTH3OSIS¬QED0 SORRY

Formal Verification Certificate

All theorems formally verified in Lean 4 with zero sorry gaps.

0 SORRY

Dual-Differentiable • Lean 4 + Mathlib • Apoth3osis Labs

The Central Question

Can proof search be turned into gradient descent? Ehrhard and Regnier’s Differential Linear Logic shows that proofs can be differentiated. This project applies DiLL semantics to SKY combinators: terms become vectors (formal linear combinations), rewrite rules extend linearly with computable Jacobians, and a gradient descent loop searches for programs satisfying I/O specifications. The chain rule is proved exact, and codereliction is shown to be the derivative of the exponential — connecting proof differentiation to classical calculus.

Original Researchers

Thomas Ehrhard
Université Paris Cité
Co-creator of Differential Linear Logic. Pioneer of quantitative semantics of proofs.
Laurent Regnier
Université d’Aix-Marseille
Co-creator of the differential λ-calculus. Formal sums and resource-sensitive semantics.

Key Verified Results

chainRule

Exact chain rule for dual-number derivatives

Derivative.lean

codereliction_is_derivative

Codereliction = derivative of exponential

Codereliction.lean

nucleusLinear_idempotent

Linear extension preserves nucleus idempotence

NucleusDifferential.lean

stepEdgesList_sound

Enumerated edges are valid Step relations

SKYMultiway.lean

stepEdges_complete

All Step successors are enumerated

SKYMultiway.lean