發送短信 : Connectedness of endo-cayley digraphs of right(left) zero union of semigroups

 ______     ______   ______    _    _    ______   
|      \\  /_   _// |      \\ | || | || |      \\ 
|  --  //   -| ||-  |  --  // | || | || |  --  // 
|  --  \\   _| ||_  |  --  \\ | \\_/ || |  --  \\ 
|______//  /_____// |______//  \____//  |______// 
`------`   `-----`  `------`    `---`   `------`