發送短信 : Twin solutions to singular Dirichlet problems

            ______   _____     _    _             
  ____     /_   _// |  __ \\  | || | ||   ____    
 |    \\    -| ||-  | |  \ || | || | ||  |    \\  
 | [] ||    _| ||_  | |__/ || | \\_/ ||  | [] ||  
 |  __//   /_____// |_____//   \____//   |  __//  
 |_|`-`    `-----`   -----`     `---`    |_|`-`   
 `-`                                     `-`