Unitary and Nonunitary Representations of the Heisenberg-Weyl Lie Algebra

This paper provides a detailed Lie-algebraic analysis of the Heisenberg-Weyl Lie algebra by constructing explicit unitary intertwining operators for tensor products of its Schrödinger representations and proving that finite-dimensional irreducible representations of the symplectic Lie algebra sp2n+2(R)\mathfrak{sp}_{2n+2}(\mathbb{R}) yield a large family of finite-dimensional, nonunitary indecomposable representations when restricted to hwn\mathfrak{hw}_n.

Andrew Douglas, Hubert de Guise, Joe Repka2026-03-09🔢 math

On the defocusing stationary nonlinear Schrödinger equation on metric graphs

This paper investigates the existence, stability, and multiplicity of ground states and stationary solutions for the defocusing nonlinear Schrödinger equation on noncompact metric graphs, establishing that while small masses always yield stable ground states, large masses lead to non-existence in the subcritical regime, with specific sharp thresholds and bifurcation behaviors identified under δ\delta-type vertex conditions.

Élio Durand-Simonnet, Damien Galant, Boris Shakarov2026-03-09🔢 math

Nonlinear Conjugate Gradient Method for Multiobjective Optimization Problems of Interval-Valued Maps

This paper proposes a nonlinear conjugate gradient method with Wolfe line search for solving unconstrained multiobjective interval optimization problems, providing proofs of global convergence for general and specific algorithmic parameters (Fletcher-Reeves, Conjugate Descent, Dai-Yuan, and modified Dai-Yuan) alongside numerical performance evaluations.

Tapas Mondal, Debdas Ghosh, Jingxin Liu, Jie Li2026-03-09🔢 math

Cohen-Macaulayness of Local Models via Shellability of the Admissible Set

This paper proves that augmented admissible sets in Iwahori-Weyl groups are dual EL-shellable, thereby resolving a conjecture of Görtz and establishing the Cohen-Macaulayness of special fibers for local models with parahoric level structure—including previously open cases in residue characteristic 2 and non-reduced root systems—through a characteristic-free, intrinsic construction that yields an explicit shelling and inductive building procedure.

Xuhua He, Felix Schremmer, Qingchao Yu2026-03-09🔢 math

Ground States of Attractive Fermi Schrödinger Systems with Ring-Shaped Potentials

This paper establishes the existence and nonexistence of ground states for mass-critical N-coupled attractive Fermi nonlinear Schrödinger systems in ring-shaped potentials based on the strength of interactions relative to a critical constant derived from a finite-rank Lieb-Thirring inequality, while also characterizing the mass concentration behavior of these states as the interaction strength approaches this critical threshold.

Yujin Guo, Yan Li, Shuang Wu2026-03-09🔢 math

Beamforming Optimization for Extremely Large-Scale RIS-Aided Near-Field Secure Communications

This paper proposes a joint optimization algorithm for transmit precoding and discrete phase-shift reflection in an extremely large-scale RIS-aided near-field secure communication system with artificial jamming, effectively maximizing secrecy rates even when eavesdroppers are located close to the RIS and in the same direction as legitimate users.

Xiaotong Xu, Qian Zhang, Yunxiao Li, Xuejun Cheng, Meihui Liu, Ju Liu2026-03-09🔢 math