Faust is the protagonist of a classic German legend. He is a scholar who is highly successful yet dissatisfied with his life, which leads him to make a pact with the Devil, exchanging his soul for unlimited knowledge and worldly pleasures. The Faust legend has been the basis for many literary, artistic, cinematic, and musical works that have reinterpreted it through the ages. "Faust" and the adjective "Faustian" imply a situation in which an ambitious person surrenders moral integrity in order to achieve power and success for a delimited term. The Faust of early books—as well as the ballads, dramas...

Go (traditional Chinese: 圍棋; simplified Chinese: 围棋; pinyin: wéiqí; Japanese: 囲碁; rōmaji: igo; Korean: 바둑; romaja: baduk; literally: "encircling game") is an abstract strategy board game for two players, in which the aim is to surround more territory than the opponent. The game was invented in ancient China more than 2,500 years ago, and is therefore believed to be the oldest board game continuously played today. It was considered one of the four essential arts of the cultured aristocratic Chinese scholar caste in antiquity. The earliest written reference to the game is generally recognized as...

In set theory, an ordinal number, or ordinal, is one generalization of the concept of a natural number that is used to describe a way to arrange a collection of objects in order, one after another. Any finite collection of objects can be put in order just by the process of counting: labeling the objects with distinct whole numbers. Ordinal numbers are thus the "labels" needed to arrange collections of objects in order. An ordinal number is used to describe the order type of a well ordered set (though this does not work for a well ordered proper class). A well ordered set is a set with a relation...