Which 'Seinfeld' character is Jerry's nemesis and a mail carrier?

Who created the original British version of 'The Office'? In which city is 'Seinfeld' set? What is the name of the diner where the 'Seinfeld' characters often eat? What is Kramer's first name in 'Seinfeld'? Who co-created 'Seinfeld' with Jerry Seinfeld? Who played Elaine Benes in 'Seinfeld'? In which city is 'Cheers' set? In 'Cheers', what is the name of the bar owner played by Ted Danson?