I need to produce an lengthy itemization of the form:

1.AAAA

1.1 aaaa

1.2 bbbb

2.BBBB

2.1 cccc

I can get:

1.AAAA

1 aaaa

2 bbbb

2.BBBB

1 cccc

easily enough, but how can I get the main division number to repeat in the subitem numeration?

Alan