發送短信 : Complexity of terms, superpositions, and generalized hypersubstitutions

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