English

Algebraic independence of solutions to multiple Lotka-Volterra systems

Logic 2025-07-29 v2 Classical Analysis and ODEs

Abstract

Consider some non-zero complex numbers ai,bi,ci,dia_i, b_i, c_i, d_i with 1in1 \leq i \leq n and the associated classical Lotka-Volterra systems {x=aixy+biyy=cixy+diy . \begin{cases} x' = a_i xy + b_i y \newline y' = c_i xy + d_i y \text{ .} \end{cases} We show that as long as bidib_i \neq d_i for all ii and {bi,di}{bj,dj}\{ b_i, d_i\} \neq \{ b_j, d_j\} for iji \neq j, any tuples (x1,y1),,(xm,ym)(x_1,y_1) , \cdots , (x_m,y_m) of pairwise distinct, non-degenerate solutions of these systems are algebraically independent over C\mathbb{C}, meaning trdeg((x1,y1),,(xm,ym)/C)=2m\mathrm{trdeg}((x_1,y_1) , \cdots , (x_m,y_m)/\mathbb{C}) = 2m. Our proof relies on extending recent work of Duan and Nagloo by showing strong minimality of these systems, as long as bidib_i \neq d_i. We also generalize a theorem of Brestovski which allows us to control algebraic relations using invariant volume forms. Finally, we completely classify all invariant algebraic curves in the non-strongly minimal, bi=dib_i = d_i case by using machinery from geometric stability theory.

Keywords

Cite

@article{arxiv.2507.17090,
  title  = {Algebraic independence of solutions to multiple Lotka-Volterra systems},
  author = {Yutong Duan and Christine Eagles and Léo Jimenez},
  journal= {arXiv preprint arXiv:2507.17090},
  year   = {2025}
}

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23 pages