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Rigidity of the timelike marked length spectrum and length-twist coordinates of singular de-Sitter tori

Martin Mion-Mouton

Abstract

In this paper, we study the closed timelike geodesics of de-Sitter tori with one singularity and prove their uniqueness in their free homotopy class. We introduce the notion of timelike marked length spectrum of such a torus, and establish its rigidity with respect to the lengths of two homotopy classes of intersection number one. We also construct length-twist coordinates on the deformation space of de-Sitter tori with one singularity.

Rigidity of the timelike marked length spectrum and length-twist coordinates of singular de-Sitter tori

Abstract

In this paper, we study the closed timelike geodesics of de-Sitter tori with one singularity and prove their uniqueness in their free homotopy class. We introduce the notion of timelike marked length spectrum of such a torus, and establish its rigidity with respect to the lengths of two homotopy classes of intersection number one. We also construct length-twist coordinates on the deformation space of de-Sitter tori with one singularity.

Paper Structure

This paper contains 29 sections, 13 theorems, 41 equations, 5 figures.

Key Result

Proposition 1

Any timelike free homotopy class of a class A de-Sitter torus with a single singularity contains a unique geodesic. Moreover, the latter is a multiple of a simple closed geodesic, and it maximizes the length among causal curves within its free homotopy class. $\blacktriangleleft$$\blacktriangleleft$

Figures (5)

  • Figure 2.1: Local de-Sitter singularity of angle $\theta$.
  • Figure 2.2: A class A singular $\mathbf{dS}^2$-torus $\mathcal{T}_{\theta,x,y}$.
  • Figure 4.1: Rectangle $\mathcal{R}_{\theta,k,l}$ of $\mathbf{dS}^2$ with area $\theta$, $\alpha$ lightlike horizontal edges and timelike vertical edges of lengths $(k,l)$.
  • Figure 5.1: Lifts of the arcs $\textcolor{DodgerBlue}{\delta}$, $\textcolor{Blue}{\gamma_$\mathsf{b}$}$ and $\gamma_\mathsf{a}^\pm$ in the universal cover $E$ of the annulus $A$ (for $n=3$).
  • Figure 5.2: Rectangle $P\subset\mathbf{dS}^2$ bounded by $\textcolor{DodgerBlue}{\delta}$, $\textcolor{Blue}{\gamma_$\mathsf{b}$}$ and $\gamma_\mathsf{a}^\pm$, and its exterior angles at vertices $v_i$.

Theorems & Definitions (31)

  • Proposition 1
  • Theorem 2
  • Theorem 3
  • Remark 2.1
  • Definition 2.2
  • Definition 2.3: mion-moutonRigiditySingularDeSitter2024
  • Lemma 2.4: mion-moutonRigiditySingularDeSitter2024
  • Definition 2.5: birmanGaussBonnetTheorem2dimensional1984
  • Proposition 2.6: birmanGaussBonnetTheorem2dimensional1984
  • Proposition 2.7: mion-moutonRigiditySingularDeSitter2024
  • ...and 21 more