Aperiodic maximisers of Lyapunov dimension: A counterexample to the unrestricted form of Eden's conjecture
Abstract
We disprove the unrestricted form of Eden's conjecture, which asserts that the maximal local Lyapunov dimension on a compact global attractor is attained at an equilibrium or a periodic orbit. For each c>4, we construct a polynomial differential equation on ℝ5 with uniformly negative divergence. Its compact global attractor has Lyapunov dimension 4+4/c, attained precisely on an invariant two-torus carrying an irrational linear flow. The maximum over all equilibria and periodic orbits is $3$. These conclusions hold both for the local dimension defined by singular values at every positive time and for the asymptotic Kaplan--Yorke dimension. The proof uses an exact singular-value identity on the whole attractor. The results of this paper are also formally verified in Lean.
Related
BibTeX
@misc{colbrook2026aperiodic,
title = {{Aperiodic maximisers of Lyapunov dimension: A counterexample to the unrestricted form of Eden's conjecture}},
author = {Matthew J. Colbrook},
howpublished = {HAL},
year = {2026},
month = sep,
url = {https://hal.science/hal-05757958v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Aperiodic maximisers of Lyapunov dimension: A counterexample to the unrestricted form of Eden's conjecture
AU - Matthew J. Colbrook
PY - 2026
DA - 2026/09/21
PB - HAL
UR - https://hal.science/hal-05757958v1
AB - We disprove the unrestricted form of Eden's conjecture, which asserts that the maximal local Lyapunov dimension on a compact global attractor is attained at an equilibrium or a periodic orbit. For each c>4, we construct a polynomial differential equation on ℝ^5 with uniformly negative divergence. Its compact global attractor has Lyapunov dimension 4+4/c, attained precisely on an invariant two-torus carrying an irrational linear flow. The maximum over all equilibria and periodic orbits is $3$. These conclusions hold both for the local dimension defined by singular values at every positive time and for the asymptotic Kaplan--Yorke dimension. The proof uses an exact singular-value identity on the whole attractor. The results of this paper are also formally verified in Lean.
ER -