[XQuery] Pecularities in rules [143][144][145]

Hi,

another peculiarity strikes me. Have a look at these rules:

[143]    ElementContentChar    ::=    Char - [{}<&] - [{}<&] 
[144]    QuotAttrContentChar    ::=    Char - ["{}<&] - ["{}<&] 
[145]    AposAttrContentChar    ::=    Char - ['{}<&] - ['{}<&] 

According to section A.1 of XQuery 1.0 (23.07.2004)

A - B has the meaning of:
matches any string that matches A but does not match B

A look at [143] says that a character is an ElementContentChar, if it is a member of character class Char an it is not equal to any of the characters '{','}','<','&' and (a second time!!!) is not equal to any of the characters '{','}','<','&'

Is there a hidden meaning I do not catch? Or is it a typo? Or is the second set of characters plain redundant?

Cheers,
Daniel Kirmse