Centaur-Barcelona

[mylonakis@lsi.upc.es (Nicos Mylonakis)]

	Dear Thierry.

	We have found a semantic problem with TYPOL. We haven't found the way 
to express negation inside a rule.

	If we have a rule such as:

	|- p(X)
	|- q(X)
	------
	|- X

	and we want to add another rule as

	|- p(x)
	|- not q(X)
	-------
	|- X
	
	We haven't found any other way to do this that building another set
not_q which is the opposite of q.

	Is there any other more simple way to do this.

	Thanks in advance.

Javier
 Perez