Indicators

[John P. Morgan]

>Date: Fri, 3 Oct 2003 15:10:26 +0100
>From: Leonard Soicher <l.h.soicher at qmul.ac.uk>

>Dear All, 
>
>This email concerns the specific merits of the "affine" indicator that JP
>has suggested, whatever we may choose to call it. Recall JP's suggestion:
>[...]
> 

>
>Following from the comments of Peter Cameron, this does not appear to
>be the case.  For example, how is a resolvable 2-(15,3,1) equivalent to
>a complete set of MOLS? 

Well of course it is not. You would have to have affine, too, in the usual 
sense, which cannot hold with these parameters. Peter C laid this out nicely for 
us.

>So it seems that the "affine-like" indicator,
>if we have one, should be true iff the block design is resolvable and
>any two blocks in different parallel classes of a resolution meet in a
>constant number \mu of points.  I would support such an "affine-like"
>indicator.  Would others?
>
>Leonard.
>

Sounds good to me. 

JP