Is "satem" a gradient?

[petegray]

Lloyd said (rightly in my opinion)
> "Satem" may be defined in a number of different ways,
...
> "Satem" may very well be a gradient concept,
> with fuzzy edges.

To my mind this is not just a matter of definitions, but a very important
reflection of the actual nature of IE and the inter-relationship of IE
dialects.

I think this is why a tree structure for PIE or IE dialects is in some ways
unhelpful - it implies distinct boundaries and divisions despite actual
evidence to the contrary.   The "UPenn Tree" being discussed on a separate
list is a poor model for some aspects of IE study.

Peter