What's the difference between tuples and sequences? Both are ordered collections that can have repeated elements. Is there a difference? Are there other terms that are used for similar concepts, and how are these terms different?

The difference seems to be:


*

*A psychological difference: people often think about the concepts differently.

*A difference in the way people encode these when reducing everything to set theory.  This is probably never a useful thing to do except when what you're doing is set theory.



Revised version six years later: In a sequence, the linear order in which things appear is essential information. In a tuple, the roles played by the different components are what is essential.
Thus at tuple may specify: longitude, latitude, point in time, temperature, humidity, barometric pressure. You could list the numbers in a different order and correspondingly list the those labels in a different order, and you'd still have the  same tuple, but not the same sequence.
