DIAL namespaces

Hi, 

How many namespaces I would need to declare in a DIAL Page?

XHTML 2, XFORMS, DISelect, and the Delivery Context Namespace for
dcn:xxx functions?

Too many from my point of view. How about having a unique namespace for
DIAL that assumes all the rest? 

Thanks and Best Wishes

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José Manuel Cantera Fonseca
Telefónica I+D