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   _____     ___      ____       ___       _____  
  / ___//   / _ \\   |  _ \\    / _ \\    / ___// 
  \___ \\  | / \ ||  | |_| ||  / //\ \\   \___ \\ 
  /    //  | \_/ ||  | .  //  |  ___  ||  /    // 
 /____//    \___//   |_|\_\\  |_||  |_|| /____//  
`-----`     `---`    `-` --`  `-`   `-` `-----`

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發送短信 : Totally geodesic surfaces and quadratic forms