names of element types

[Ed Shaya]

XML element type names use XML Name patterns.  Here is the definition of 
Name from the XML 1.0 Rec (4th edition):


          Names and Tokens
          [4]       NameChar       ::=       Letter | Digit | '.' | '-'
          | '_' | ':' | CombiningChar | Extender
          [5]       Name       ::=       (Letter | '_' | ':') (NameChar)*


Therefore element names can only start with Letter, _, or :.  And, in 
fact Protege would not allow a Class "21cmLine" but would allow  
"_21cmLine".

Ed