Thanks very much for your help. Sometimes I do put in the dots and sometimes I don't, and I didn't realize it was so crucial. It is a little worrisome that there is no error message: it evaluates either way, but sometimes with the wrong answer.
Anyway, thanks again for your help,
This archive was generated by hypermail 2b29 : 06/25/17-10:40:02 AM Z CEST