Month 2026-02 — HEPLean/PhysLean: Delivered Release v4.27.0 with expanded math/physics constructs and Lean simplification optimization. Implemented refinements to variational calculus and quantum field theory constructs, and tightened Lean's simplification logic to improve clarity and performance in mathematical derivations. Lint and stability improvements accompany the release to reduce noise in derivations and builds.

August 2025 performance summary for leanprover-community/mathlib4. Focused on API modernization and maintainability with a targeted refactor of cross product notation. Delivered a Unicode cross product notation update and prepared the codebase for long-term consistency across mathlib4.

June 2025 performance summary for HEPLean/PhysLean focused on core modeling accuracy, modularity, and developer ergonomics. Delivered foundational Harmonic Wave core and electromagnetism (EM) math improvements, introduced a Polarization and Optics module for monochromatic representations and polarization ellipse, and added a Direction API to support unit-vector handling in plane-wave calculations. These efforts improved simulation fidelity, reduced maintenance burden, and enabled faster feature delivery. Notable work included refactors of orthonormal proofs, documentation improvements, and groundwork for monochromatic representations. Key commits span Harmonic Wave setup and orthonormal proof refactors, polarization ellipse and new optics files, Direction API refinements, and docstring updates across the codebase.

May 2025 performance summary for HEPLean/PhysLean: Delivered core EM physics capabilities, stabilized the API surface, and strengthened code quality. Key advancements include EM wave equation modeling with plane wave handling and dt/dx separation, development of orthogonal E, B, and s relationships for traveling EM waves, a refactor to unfold-to-read/write (rw) pathways, and extensive linting/formatting improvements. Additionally, parameter validation now enforces positive mu and epsilon, with import path fixes to reduce build/import friction. Collectively, these changes enhance simulation accuracy, reduce maintenance risk, and accelerate onboarding and future development.

April 2025: Delivered substantial enhancements to the HEPLean/PhysLean math framework, expanding space and derivative modeling, improving naming consistency, and strengthening code quality. Key feature deliveries include spaceGrad, basis and coordinate definitions, and Space/Time derivatives, enabling more accurate PDE representations and physics-based simulations; introduced vector identities and the property that dt and curl commute. Major refactors and quality improvements included moving deriv_commute to a new file, namespace fixes, and extensive lint/style cleanups across the codebase. The release also extended Electromagnetic/Optical Medium Modeling with homogeneous media support, and introduced free-variable concepts and IsFree utilities to better express and validate symbolic constraints. Additional improvements covered smul and linearity, Laplacian/curl lemmas with updated delta notation and standardized lemma names, and utilities like fderiv_curry/refactor with fderiv_swap. Overall, these changes increase modeling capability, reliability, and maintainability, delivering business value by enabling richer physics models with fewer defects and a cleaner foundation for future features.