Whether directional transience implies ballisticity in iid environments

For nearest-neighbor random walk in an iid uniformly elliptic environment on Zᵈ, d≥2, does almost-sure transience in a fixed direction force a deterministic limiting velocity with positive projection in that direction?

Why it matters and what counts as progress

Why it matters: The implication would turn directional escape into positive speed without quantitative drift or exit assumptions.

What counts as progress: A ballisticity theorem under precisely these higher-dimensional hypotheses, or a transient zero-speed example satisfying them; dimension one has different behavior.

How the problem developed

  1. 23 Sept 2026 · Reported theorem [1][2]

    OpenAI Reported that almost-sure transience in a fixed direction implies a deterministic limiting velocity with positive projection in that direction for nearest-neighbor iid uniformly elliptic environments on ℤᵈ, d ≥ 2.

AI contribution

Sources

  1. OpenAI directional-ballisticity manuscript
  2. Directional transience implies ballisticity
  3. OpenAI ballisticity formalization scope
  4. OpenAI ballisticity Lean theorem
  5. Directional-ballisticity comparator statement
  6. OpenAI mathematics release account
Website timeline

Publication dates and editorial changes.