🔢 mathematics

Modular Phase Geometry of Semiprime Residue States: Exact Character Laws and Virtual Physics Assays

This paper introduces Modular Phase Geometry as a finite arithmetic framework for semiprime residue states that combines exact character laws and product properties with virtual physics assays to demonstrate measurable structured signatures, while explicitly clarifying that the construction is not a factorization algorithm nor a claim of physical fundamentality.

Giuseppe Maffei2026-09-14
🔢 mathematics

Koopman Eigenfunctionals Associated with Floquet Multipliers of Attracting Periodic Orbits in Parabolic Semiflows

This paper constructs scalar Koopman eigenfunctionals for exponentially attracting periodic orbits in semilinear parabolic semiflows by deriving them from dominant Floquet multipliers via a direct Laplace-limit argument on isochron sections, extending them to continuous time, and analyzing their behavior regarding phase-frequency shifts and the topological obstructions caused by negative multipliers.

Yuanchao Xu2026-09-10
🔢 mathematics

Sparse observations of semilinear parabolic equations: spatial maxima and threshold times

This paper establishes optimal lower bounds for the first threshold time of semilinear parabolic equations by combining classical extremal extensions of sparse, bounded-error spatial observations with scalar comparison equations, while explicitly linking the required sensor density to the metric NN-center problem and validating the approach through one-dimensional and industrial geometry examples.

Uldis Strautins2026-09-09
🔢 mathematics

Pointwise Monotonicity of the Allen--Cahn Flow and Dynamical Limitations of Energy-Stable Schemes

This paper establishes that pointwise monotonicity, a local dynamical criterion distinct from energy stability, is preserved by the exact Allen-Cahn flow and fully implicit Euler method but often violated by widely used second-order energy-stable schemes, leading to artificial delays or incorrect pointwise increments even in the presence of active diffusion.

Pansheng Li, Dongling Wang2026-09-08