_Op. cit._, p.13

Formal concepts are illustrated with a miniature example, with:

* Objects O = {fruit, vegetable}
* Attributes A = {green, yellow, purple}

The formal context given is \\(\lbrace (fruit,orange), (fruit,green), (vegetable,purple) \rbrace\\).

Writing this using arrows for the tuples:

* \\(fruit \rightarrow orange\\)
* \\(fruit \rightarrow green\\)
* \\(vegetable \rightarrow purple\\)

And reversing the direction to match language scanning:

* \\(orange \leftarrow fruit\\)
* \\(green \leftarrow fruit\\)
* \\(purple \leftarrow vegetable\\)