Conjugate locus on SE(2)
Where rotating sub-Riemannian geodesics stop being optimal, with the counting theorems checked by the Lean kernel.
Maintained by Igor Moiseev
Articles
Research graph
Findings
- ConfirmedE:se2-concrete7 Oct 2026Imported
Concrete instance for 0 < k < 1
Kernel-checked: `JacobiConcrete.first_time_unique` compiles and depends only on propext, Classical.choice and Quot.sound.
- ConfirmedE:se2-T417 Oct 2026Imported
Theorem 4.1 — two conjugate times per Maxwell cell
Kernel-checked: `JacobiFull.roots_ncard` compiles and depends only on propext, Classical.choice and Quot.sound.
- ConfirmedE:se2-T34c7 Oct 2026Imported
Theorem 3.4 (complete) — nothing earlier
Kernel-checked: `JacobiFull.first_time_complete` compiles and depends only on propext, Classical.choice and Quot.sound.
- ConfirmedE:se2-T347 Oct 2026Imported
Theorem 3.4 — uniqueness of the first conjugate time
Kernel-checked: `JacobiFull.exact_first_time` compiles and depends only on propext, Classical.choice and Quot.sound.
- ConfirmedE:se2-crossing7 Oct 2026Imported
Crossing lemma
Kernel-checked: `CrossingData.crossing` compiles and depends only on propext, Classical.choice and Quot.sound.
Claims
- CrossingData.crossing · lean
For every phase ψ there is exactly one parameter p in [lo, hi] and one branch σ = ±1 whose value equals ψ modulo the period 2K.
- JacobiFull.exact_first_time · lean
For every phase ψ there is exactly one p in [p₀, p₁] with J₂(ψ + p, p) = 0.
Passed· 18.0s · 1 d agoaxioms: propext, Classical.choice, Quot.sound - JacobiFull.first_time_complete · lean
For every phase there is exactly one conjugate time in (0, p₁], and it lies in [p₀, p₁].
Passed· 24.5s · 15 h agoaxioms: propext, Classical.choice, Quot.sound - JacobiFull.roots_ncard · lean
Away from K = 2E, every phase has exactly 2N conjugate times before the end of the N-th Maxwell cell: two per cell, none before the first.
- JacobiConcrete.first_time_unique · lean
For the concrete Jacobi elliptic data with modulus 0 < k < 1, the first conjugate time is unique for every phase.