Concept

Definition

Concept

A concept $c\in C$, where $C$ is a concept class, is a binary classification function

$$c:\mathcal{X}\to \{0,1\},$$

where $\mathcal{X}$ is the set of instances.

For an instance $x\in \mathcal{X}$, it holds that

$$\begin{array}{rl}c(x)& =1⟺x\text{ is positive for the concept }c,\text{ and}\\ c(x)& =0⟺x\text{ is negative for the concept }c.\end{array}$$