Hello once more, as explained in section 10.1 of the user guide, there are few special expressions that produce series and that are somewhat at odds with the usual hansl syntax, for historical path-dependent reasons. One is "time", which can either be used as "genr time" (not "series time", which as per standard syntax produces a new series full of missings); or it can be used in assignments such as "series x = time", even when 'time' wasn't previously defined or created. Wouldn't it be more consistent to have a dollar accessor $time instead? This would be just like the change from 'pi' to '$pi' in the past. Pragmatically, "time" should stay for compatibility, but I believe $time should be preferred. thanks sven