arXiv subjects

Jonathan Hellwig

Publications and source records attributed to Jonathan Hellwig.

3 recordsLinked to original sources

arXiv2026

A Deductive Refinement Calculus for Differential-Algebraic Programs

This paper presents differential-algebraic refinement logic (dARL) with which one can deductively verify both properties and relations of differential-algebraic programs (DAPs) that extend hybrid dynamical systems with differential-algebraic equations (DAEs). A refinement calculus is introduced that enables the sound comparison of trajectories of differential-algebraic equations, crucially utilizing a novel trace-based semantics. This enables the incremental verification/simplification of complicated DAEs, while ensuring correctness at each step by the soundness of the calculus. The calculus is shown to be complete for certifying index reductions of DAEs, providing trustworthy syntactic proofs of correctness at each step of the reduction.

cs.LO↗

arXiv2025

From Zonotopes to Proof Certificates: A Formal Pipeline for Safe Control Envelopes

Synthesizing controllers that enforce both safety and actuator constraints is a central challenge in the design of cyber-physical systems. State-of-the-art reachability methods based on zonotopes deliver impressive scalability, yet no zonotope reachability tool has been formally verified and the lack of end-to-end correctness undermines the confidence in their use for safety-critical systems. Although deductive verification with the hybrid system prover KeYmaera X could, in principle, resolve this assurance gap, the high-dimensional set representations required for realistic control envelopes overwhelm its reasoning based on quantifier elimination. To address this gap, we formalize how control-invariant sets serve as sound safety certificates. Building on that foundation, we develop a verification pipeline for control envelopes that unites scalability and formal rigor. First, we compute control envelopes with high-performance reachability algorithms. Second, we certify every intermediate result using provably correct logical principles. To accelerate this certification, we offload computationally intensive zonotope containment tasks to efficient numerical backends, which return compact witnesses that KeYmaera X validates rapidly. We show the practical utility of our approach through representative case studies.

cs.LO↗

arXiv2025

A Real-Analytic Approach to Differential-Algebraic Dynamic Logic

This paper introduces a proof calculus for real-analytic differential-algebraic dynamic logic, enabling correct transformations of differential-algebraic equations. Applications include index reductions from differential-algebraic equations to ordinary differential equations. The calculus ensures compatibility between differential-algebraic equation proof principles and (differential-form) differential dynamic logic for hybrid systems. One key contribution is ghost switching which establishes precise conditions that decompose multi-modal systems into hybrid systems, thereby correctly hybridizing sophisticated differential-algebraic dynamics. The calculus is demonstrated in a proof of equivalence for a Euclidean pendulum to index reduced form.

cs.LO↗