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  ____     _    _    __   __   _    _   __    __  
 |  _ \\  | || | ||  \ \\/ // | || | || \ \\ / // 
 | |_| || | || | ||   \   //  | || | ||  \ \/ //  
 | .  //  | \\_/ ||   / . \\  | \\_/ ||   \  //   
 |_|\_\\   \____//   /_//\_\\  \____//     \//    
 `-` --`    `---`    `-`  --`   `---`       `

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Text this: On (pa, p, pa, pa-1)-relative difference sets