Determine asymptotic laws near infinite-period trajectories

Determine whether the functional mixing, geometric mixing, and curve-growth laws for two-dimensional stationary incompressible Hamiltonian flows retain the same algebraic orders or acquire logarithmic or different algebraic corrections when trajectories approach infinite-period orbits and their limiting equilibria.

Background

The main theorems exclude infinite-period trajectories because their trajectories converge to equilibria in forward and backward time, whereas the action-angle coordinates and uniform estimates used in the paper are constructed in regular regions of finite-period trajectories. Extending the analysis across such trajectories requires quantitative control near the limiting equilibria and a replacement for the periodic coordinate chart.

The unresolved issue is whether the inverse-time and linear-growth laws established away from infinite-period trajectories persist unchanged, or whether the approach to separatrices produces logarithmic or other algebraic corrections.

References

The arguments of this paper do not determine whether the resulting laws retain the same algebraic orders or acquire logarithmic or different algebraic corrections.

— Geometric and functional mixing by 2D stationary incompressible flows  (2609.34168 - Hu et al., 28 Sep 2026) in Section 11, subsection “Perspectives,” item (ii), “Infinite-period trajectories”