"Lisa, in this house, we obey the laws of thermodynamics!" - Homer Simpson
"I have my standards. They may be low, but I have them!" - Bette Middler
"It's a book about a Spanish guy named Manual. You should read it." - Dilbert
When doing homework, Google is your friend! Check out the article in the Wikipedia, unless your reason for posting was to get a "ready to use" answer instead of just getting someone to do your research and present it for you.
To mangle an old line from Cheech and Chong: "If it looks like homework, smells like homework, and tastes like homework..."
What specific questions about tuples can we answer? Especially this time of year, you aren't likely to get much more response to any question that includes the phrase "discuss in detail" because that makes it sound like someone trying to get us to do their homework.
If you really want help, put forth at least enough effort to make it easy to help you. Narrow down your question to something specific so that you think it can be answered with a word or a sentance, not a reference to an article. If all you are is a student looking for someone to do your homework, just go away quietly and we won't mind much).