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TMF, 2025 Volume 222, Number 1, Pages 81–98 (Mi tmf10714)

Algebro-geometric quasiperiodic solutions of the nonlocal reverse space–time sine-Gordon equation

Liang Guana, Xianguo Gengb, Xue Genga

a School of Mathematics and Statistics, Anyang Normal University, Anyang, Henan, China
b School of Mathematics and Statistics, Zhengzhou University, Zhengzhou, Henan, China

Abstract: Based on the theory of hyperelliptic curves, the algebraic curve method is extended to construct algebro-geometric quasiperiodic solutions of nonlocal reverse space–time soliton equations. The nonlocal reverse space–time sine-Gordon equation is chosen as an example to illustrate our method. Given the Lax matrix of the nonlocal reverse space–time sine-Gordon equation, we introduce an algebraic hyperelliptic curve $\mathcal K_n$ of genus $n$, from which the Dubrovin-type equations, a meromorphic function $\phi$, and a Baker–Akhiezer function $\psi_{1}$ are found. Using the theory of algebraic curves, the nonlocal reverse space–time sine-Gordon flows are straightened by using the Abel–Jacobi coordinates. In accordance with the asymptotic properties of the Baker–Akhiezer function, we construct explicit theta-function representations of the Baker–Akhiezer function and the meromorphic function, including that for solutions of the nonlocal reverse space–time sine-Gordon equation.

Keywords: nonlocal reverse space–time sine-Gordon equation, Baker–Akhiezer function, Riemann theta function, algebro-geometric quasiperiodic solution.

MSC: 35Q51,37K10,35Q58,35L65

Received: 28.02.2024
Revised: 09.06.2024

DOI: 10.4213/tmf10714


 English version:
Theoretical and Mathematical Physics, 2025, 222:1, 69–84

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© Steklov Math. Inst. of RAS, 2026