[slightly OT]Universal Turing machine in XSLT

Hi,

    Found this on the web :

http://www.unidex.com/turing/utm.htm

    It seems to me that one of the implicit assumptions used by a UTM
is that it is able to write any specified symbol. If I read the XML
spec correctly though, certain symbols are not legal (for example
0x0000 is not a valid Unicode codepoint). That being the case, can
this UTM really be valid?

Thanks,
Kenneth