Clarification for wsdl:required attribute needed

Folks, 

In review of the draft, it is not clear to me what we are assuming with
respect to the presence of an extension in WSDL without using
wsdl:required attribute. 

Do we assume that it is optional (i.e. wsdl:required="false"), or is it
undefined? In reading the section about mandatory extensions, it seems
that such extensions are assumed to be optional (since they are
definitely NOT marked with wsdl:required attribute and considered to be
non-mandatory per that section). If this is the semantics, I propose
that we include a clarification that the default value for the
wsdl:required attribute is false and extensions that appears in a WSDL
document are considered to be marked to be optional. If that is not the
intended semantics, I would like to know what it means to put an
extension in WSDL, not mark it required optional/required and what would
that tertiary logic implies? 

If I have missed a discussion and resolution on this, a pointer to the
resolution will be appreciated. 

Thanks, 

--umit