Hi,

I am new here, so apologies for any miscommunication.

I am going through the book Discrete Structures, Logic, and Computability by James L. Hein

One of the problems defines tuples using sets:

- ( ) = the empty set
- (x) = {x}
- (x,y) = {x,{x,y}}

It's the last item I do not understand - can someone explain it to me in an intuitive manner?