發送短信 : On Some Properties of Baire-1 Functions

  _____     _____    __   _      ___      ______  
 /  ___||  |  ___|| | || | ||   / _ \\   /_   _// 
| // __    | ||__   | '--' ||  | / \ ||  `-| |,-  
| \\_\ ||  | ||__   | .--. ||  | \_/ ||    | ||   
 \____//   |_____|| |_|| |_||   \___//     |_||   
  `---`    `-----`  `-`  `-`    `---`      `-`'