BiHom-Lie brackets and the Toda equation

Fuente: arXiv
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Autores principales: Gai, Botong, Li, Chuanzhong, Sun, Jiacheng, Wang, Shuanhong, Zhu, Haoran
Formato: Preprint
Publicado: 2025
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author Gai, Botong
Li, Chuanzhong
Sun, Jiacheng
Wang, Shuanhong
Zhu, Haoran
author_facet Gai, Botong
Li, Chuanzhong
Sun, Jiacheng
Wang, Shuanhong
Zhu, Haoran
contents We introduce a BiHom-type skew-symmetric bracket on $\mathfrak{gl}(V)$ built from two commuting inner automorphisms $α=Ad_ψ$ and $β=Ad_ϕ$ with $ψ,ϕ\in \mathfrak{gl}(V)$ and integers $i,j$. We prove that $(\mathfrak{gl}(V),[\cdot,\cdot]^{(i,j)}_{(ψ,ϕ)},α,β)$ is a BiHom--Lie algebra, and we study the Lax equation obtained by replacing the commutator in the finite nonperiodic Toda lattice by this bracket. For the symmetric choice $ϕ=ψ$ with $(i,j)=(0,0)$, the deformed flow is equivariant under conjugation and becomes gauge-equivalent, via $\widetilde L=ψ^{-1}Lψ$, to a Toda-type Lax equation with a conjugated triangular projection. In particular, scalar deformations amount to a constant rescaling of time. On embedded $2\times2$ blocks, we derive explicit trigonometric and hyperbolic formulas that make symmetry constraints (e.g. tracelessness) transparent. In the asymmetric hyperbolic case, we exhibit a trace obstruction showing that the right-hand side is generically not a commutator, which amounts to symmetry breaking of the isospectral property. We further extend the construction to the weakly coupled Toda lattice with an indefinite metric and provide explicit $2\times2$ solutions via an inverse-scattering calculation, clarifying and correcting certain formulas in the literature. The classical Toda dynamics are recovered at special parameter values.
format Preprint
id arxiv_https___arxiv_org_abs_2512_15523
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle BiHom-Lie brackets and the Toda equation
Gai, Botong
Li, Chuanzhong
Sun, Jiacheng
Wang, Shuanhong
Zhu, Haoran
Exactly Solvable and Integrable Systems
Rings and Algebras
We introduce a BiHom-type skew-symmetric bracket on $\mathfrak{gl}(V)$ built from two commuting inner automorphisms $α=Ad_ψ$ and $β=Ad_ϕ$ with $ψ,ϕ\in \mathfrak{gl}(V)$ and integers $i,j$. We prove that $(\mathfrak{gl}(V),[\cdot,\cdot]^{(i,j)}_{(ψ,ϕ)},α,β)$ is a BiHom--Lie algebra, and we study the Lax equation obtained by replacing the commutator in the finite nonperiodic Toda lattice by this bracket. For the symmetric choice $ϕ=ψ$ with $(i,j)=(0,0)$, the deformed flow is equivariant under conjugation and becomes gauge-equivalent, via $\widetilde L=ψ^{-1}Lψ$, to a Toda-type Lax equation with a conjugated triangular projection. In particular, scalar deformations amount to a constant rescaling of time. On embedded $2\times2$ blocks, we derive explicit trigonometric and hyperbolic formulas that make symmetry constraints (e.g. tracelessness) transparent. In the asymmetric hyperbolic case, we exhibit a trace obstruction showing that the right-hand side is generically not a commutator, which amounts to symmetry breaking of the isospectral property. We further extend the construction to the weakly coupled Toda lattice with an indefinite metric and provide explicit $2\times2$ solutions via an inverse-scattering calculation, clarifying and correcting certain formulas in the literature. The classical Toda dynamics are recovered at special parameter values.
title BiHom-Lie brackets and the Toda equation
topic Exactly Solvable and Integrable Systems
Rings and Algebras
url https://arxiv.org/abs/2512.15523