10 Mar 2005
CS 3243 - FOL and Prolog
42
Points to consider
lVariables are bound by Prolog, not by the programmer
You cant assign a
value to a variable.
lSuccessive user prompts ; cause
the interpreter to return all terms
that can be substituted for X.
They are returned in
the order found.
Order is
important
l PROLOG adopts the closed-world assumption:
All knowledge of the
world is present in the database.
If a term is not in
the database assume is false.
Prologs yes = I can
prove it, no = I cant prove it.
; means Or
, means And
Two
things to think about:
When
would the closed-world assumption lead to false inferences?
When
would the different ordering of solutions cause problems?