17 Feb 2005
CS 3243 - Constraint Satisfaction
32
More on arc consistency
nArc
consistency is based on a very simple concept
nif we can look at just one constraint and see that x=v
is impossible …
nobviously we can remove the value x=v from consideration
nHow
do we know a value is impossible?
nIf
the constraint provides no support for the value
ne.g.
if Dx = {1,4,5} and Dy = {1, 2, 3}
nthen
the constraint x > y provides no support for x=1
nwe
can remove x=1 from Dx