"Teichmuller theory"의 두 판 사이의 차이

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48번째 줄: 48번째 줄:
 
<h5>shear coordinate</h5>
 
<h5>shear coordinate</h5>
  
*  
+
* E an edge (diagonal), T a triangulation (collection of edges or diagonals)
 +
* <math>\Sigma</math> a point in the Teichmuller space (metric)
 +
* shear coordinate <math>\tau_{\Sigma}(E,T)</math>
 
* for tropical version of shear coordiante, see [[lamination and tropical shear coordinates on a marked surface|lamination and shear coordinates on a marked surface]]
 
* for tropical version of shear coordiante, see [[lamination and tropical shear coordinates on a marked surface|lamination and shear coordinates on a marked surface]]
  
59번째 줄: 61번째 줄:
 
<h5>decorated Teichmuller space</h5>
 
<h5>decorated Teichmuller space</h5>
  
\def decorated Teichmuller space \tilde{T}(S,M) is
+
\def decorated Teichmuller space <math>\tilde{T}(S,M)</math> is
  
* a point in T(S,M)
+
* a point in T(S,M) (i.e.  hyperbolic metric)
* a choic of horocycle around each cusp from M
+
* a choic of horocycle around each cusp from M (i.e. marked point)
  
\def (Penner) For a arc A in (S,M) and \Sigma\in\tilde{T}(S,M),
+
\def (Penner) For a arc A in (S,M) and <math>\Sigma\in\tilde{T}(S,M)</math>,
  
 
the length of A with respect to \Sigma is
 
the length of A with respect to \Sigma is
72번째 줄: 74번째 줄:
 
 
 
 
  
The \lambda - length is \lambda_{\Sigma}(A) : = e^{l_{\Sigma}(A)/2}
+
The <math>\lambda</math> - length is <math>\lambda_{\Sigma}(A) : = e^{l_{\Sigma}(A)/2}</math>
  
 
Note  :  \lambda_{\Sigma}(A) in \mathbb{R}_{> 0 }
 
Note  :  \lambda_{\Sigma}(A) in \mathbb{R}_{> 0 }

2011년 8월 13일 (토) 08:18 판

introduction

 

 

review of hyperbolic geometry

 

 

Teichmuller space of a marked surface

Given marked surface (S,M) , the Teichmuller space T(S,M) is the space of metrics on (S,M) such that

  • are hyperbolic  (constant curvature -1)
  • have geodesic boundary at boundary of S
  • local neighborhood of point on boundary S can be mapped isometrically to neighborhood of a point here on one side of geodesic
  • have cusps at points in M

Considered up to diffeomorphism homotopic to identity.

Facts

(1) T(S,M) contractible

(2) T(S,M) is manifold of dimension 6g-6+2p+3b+c where g = genus, p=# of puncture, b = # boundary component, c=# of marked points on boundary

 

 

shear coordinate
  • E an edge (diagonal), T a triangulation (collection of edges or diagonals)
  • \(\Sigma\) a point in the Teichmuller space (metric)
  • shear coordinate \(\tau_{\Sigma}(E,T)\)
  • for tropical version of shear coordiante, see lamination and shear coordinates on a marked surface

 

 

 

decorated Teichmuller space

\def decorated Teichmuller space \(\tilde{T}(S,M)\) is

  • a point in T(S,M) (i.e.  hyperbolic metric)
  • a choic of horocycle around each cusp from M (i.e. marked point)

\def (Penner) For a arc A in (S,M) and \(\Sigma\in\tilde{T}(S,M)\),

the length of A with respect to \Sigma is

l_{\Sigma(A) = length on geodesic representative of A between intersections with horocycles around ends. (negative if 2 horocycles intersect) 

 

The \(\lambda\) - length is \(\lambda_{\Sigma}(A) : = e^{l_{\Sigma}(A)/2}\)

Note  :  \lambda_{\Sigma}(A) in \mathbb{R}_{> 0 }

 

\prop

In an ideal quadrilateral, the Ptolemy relation holds.

 

\thm (Penner)

For any triangulation (A_{i})

 

 

 

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