English

Equidistribution of polynomially bounded o-minimal curves in homogeneous spaces

Dynamical Systems 2026-02-25 v2 Logic

Abstract

We extend Ratner's theorem on equidistribution of individual orbits of unipotent flows on finite volume homogeneous spaces of Lie groups to trajectories of non-contracting curves definable in polynomially bounded o-minimal structures. To be precise, let φ:[0,)SL(n,R)\varphi:[0,\infty)\to \text{SL}(n,\mathbb R) be a continuous map whose coordinate functions are definable in a polynomially bounded o-minimal structure; for example, rational functions. Suppose that φ\varphi is non-contracting; that is, for any linearly independent vectors v1,,vkv_1,\ldots,v_k in Rn\mathbb R^n, φ(t).(v1vk)↛0\varphi(t).(v_1\wedge\cdots\wedge v_k)\not\to0 as tt\to\infty. Then, there exists a unique smallest subgroup HφH_\varphi of SL(n,R)\text{SL}(n,\mathbb R) generated by unipotent one-parameter subgroups such that φ(t)Hφg0Hφ\varphi(t)H_\varphi\to g_0H_\varphi in SL(n,R)/Hφ\text{SL}(n,\mathbb R)/H_\varphi as tt\to\infty for some g0SL(n,R)g_0\in \text{SL}(n,\mathbb R). Let GG be a closed subgroup of SL(n,R)\text{SL}(n,\mathbb R) and Γ\Gamma be a lattice in GG. Suppose that φ([0,))G\varphi([0,\infty))\subset G. Then HφGH_\varphi\subset G, and for any xG/Γx\in G/\Gamma, the trajectory {φ(t)x:t[0,T]}\{\varphi(t)x:t\in [0,T]\} gets equidistributed with respect to the measure g0μLxg_0\mu_{Lx} as TT\to\infty, where LL is a closed subgroup of GG such that Hx=Lx\overline{Hx}=Lx and LxLx admits a unique LL-invariant probability measure, denoted by μLx\mu_{Lx}. A crucial new ingredient in this work is proving that for any finite-dimensional representation VV of SL(n,R)\text{SL}(n,\mathbb R), there exist T0>0T_0>0, C>0C>0, and α>0\alpha>0 such that for any vGv\in G, the map tφ(t)vt\mapsto \|\varphi(t)v\| is (C,α)(C,\alpha)-good on [T0,)[T_0,\infty).

Keywords

Cite

@article{arxiv.2407.04935,
  title  = {Equidistribution of polynomially bounded o-minimal curves in homogeneous spaces},
  author = {Michael Bersudsky and Nimish A. Shah and Hao Xing},
  journal= {arXiv preprint arXiv:2407.04935},
  year   = {2026}
}