In machine learning theory and artificial intelligence, a concept 
over a domain 
is a Boolean function 
. A collection of concepts
is called a concept class.
In context-specific applications, concepts are usually thought to assign either a "positive" or "negative" outcome (corresponding to range values
of 1 or 0, respectively) to each element 
of the domain 
. In that way, concepts are the fundamental component of learning
theory.
