發送短信 : Graphs realised by r.e. equivalence relations

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