Possible error in the specification of the degree element.

Hi,
I've checked the errata document, and couldn't find anything on this
subject, so I thought I would report it.
There seems to be an inconsistency in the MathML spec regarding the
signature of the <root> content element. This is what the validation grammar
has to say about it:
--- Snip ---
| (root degree? _mmlarg) 
---- Snip ----
This is what chapter 4.4.5.7 Degree (degree) has to say about it:
---- Snip ----
<apply>
  <root/>
  <degree><ci type='integer'> n </ci></degree>
  <ci> a </ci>
</apply>
---- Snip ----

The validation grammar and the description coincide. However, appendix C
(which is the most formal definition of the content elements) says:
---- Snip ----
This is the binary operator used to construct the nth root of an expression.
The first argument "a" is the expression and the second object "n" denotes
the root, as in ( a ) ^ (1/n)
Signature 
	( anything , anything) -> root 
Example 
	nth root of a
						
	<apply><root/>
	<ci> a </ci>
	<ci> n </ci>
	</apply>
---- Snip ----

Are chapter 4 and the validation grammar correct, or is appendix C correct?
(Or was the intention to make the use of the degree element optional?)
Thanks for clearing this up,

Michael McCarthy.