Sequence type and other related questions

The section on sequences 
( states that a sequence 
that contains a single item is indistinguishable from the item itself. 
Among other things this means that a sequence with one item in it has 
the same type as that item. Therefore sequences must have types.

This raises a couple of questions.

What is the type of a sequence with two (or more) items in it which are 
potentially different ?

Is it just a generic sequence type, is it the type which is the closest 
ancestor of all the item types, or something else ?

What is the type of an empty sequence ?

Can the empty sequence be a singleton, i.e. are all empty sequences the 
same ? There was an issue raised that asked for empty sequences to be 
typed but the resolution was private.

Apologies if these questions have already been answered elsewhere. I 
have looked and could not find anything.

Received on Tuesday, 15 July 2003 06:03:46 UTC