Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
G53KRR 2007-8 model answers Question 1 (a) A representation language is a formal language used to repre-
 

Summary: G53KRR 2007-8 model answers
Question 1 (a) A representation language is a formal language used to repre-
sent information. Reasoning or inference mechanism helps to extract
more information from what is explicitly represented. Possible ex-
amples include: first order logic as a representation language and
resolution as an inference mechanism; production system rules as
representation language, and forward chaining as an inference mech-
anism.
(b) The main problems are: computational intractability and inability to
express default rules, probabilistic and approximate knowledge.
(c) An inference system is sound (with respect to some semantical no-
tion of entailment) if it only derives sentences which are entailed by
the premises. It is complete if it can derive all sentences which are
entailed by the premises.
(d) Resolution is sound but not complete; for example it is impossible
to derive p ¬p by resolution from an empty set of sentences. It is
however complete for refutation: if an empty clause (a contradiction)
is entailed by a set of sentences, then it is possible to derive it using
resolution.
Question 2 (a) S1 x(Plant(x) ¬Water(x) ¬Survive(x))

  

Source: Alechina, Natasha - School of Computer Science, University of Nottingham

 

Collections: Computer Technologies and Information Sciences