Quadratic Bureau-Guillot systems with the first and second Painlevé transcendents in the coefficients. Part I: geometric approach and birational equivalence

This paper revisits quadratic Bureau-Guillot systems containing first and second Painlevé transcendent coefficients, utilizing Okamoto's geometric approach and iterative polynomial regularisation to establish their birational equivalence, resolve the Painlevé equivalence problem for non-rational meromorphic coefficients, and identify a Hamiltonian formulation for one of the systems.

Marta Dell'Atti, Galina FilipukWed, 11 Ma🌀 nlin

The half-wave maps equation on T\mathbb{T}: Global well-posedness in H1/2H^{1/2} and almost periodicity

This paper establishes global well-posedness in the critical energy space H1/2H^{1/2} and proves almost periodicity in time for the half-wave maps equation on the one-dimensional torus by leveraging its integrable Lax pair structure to derive explicit solution formulae and a general stability principle that extends to matrix-valued cases and companion results on the real line.

Patrick Gérard, Enno LenzmannTue, 10 Ma🔢 math

Invariant Reduction for Partial Differential Equations. IV: Symmetries that Rescale Geometric Structures

This paper extends the framework of invariant reduction for partial differential equations to handle geometric structures that are rescaled rather than strictly invariant by symmetries, establishing a shift rule that explains the emergence or loss of invariance in reduced systems and enabling the geometric construction of exact solutions without relying on integrability structures like Lax pairs.

Kostya Druzhkov, Alexei CheviakovThu, 12 Ma🌀 nlin

Dimers and Beauville integrable systems

This paper proves that for the standard triangle polygon (corresponding to the toric surface P2\mathbb{P}^2), the spectral transform establishes a birational isomorphism between the Goncharov-Kenyon cluster integrable system and the Beauville integrable system by showing that it intertwines their respective Poisson structures, thereby demonstrating that Beauville integrable systems admit cluster algebra structures.

Terrence George, Giovanni InchiostroMon, 09 Ma🔢 math

Gaussian free field convergence of the six-vertex model with 1Δ12-1\leq\Delta\leq-\frac12

The paper proves that the height function of the six-vertex model on Z2\mathbb{Z}^2 with spectral parameter Δ[1,1/2]\Delta \in [-1, -1/2] converges to a full-plane Gaussian free field in the scaling limit, a result that extends to anisotropic weights via a suitable lattice embedding.

Hugo Duminil-Copin, Karol Kajetan Kozlowski, Piet Lammers, Ioan ManolescuMon, 09 Ma🔢 math