RE: A challenge.. Group Periods of Data (1..5, 2..8,

> The challend did state that the periods listed were arbitrary
> (unkown).  Any way to drive your solution without parameters or
> pre-existing variables defining these periods?

I wondered what you meant by that - I still do. You mean you want the
stylesheet to detect a time at which no sessions are alive, and use that as
a boundary between periods? What if there is no such time? What if there are
several? You need to specify the problem more precisely.

Michael Kay
http://www.saxonica.com/