Groupoid

:In addition to the present meaning, the term "groupoid" is also used for a magma: a set with an arbitrary binary operation on it. This encyclopedia does not use that sense of this word.

Related Topics:
Magma - Set - Binary operation

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In mathematics, especially in category theory and homotopy theory, a groupoid is a concept (first developed by Heinrich Brandt in 1926) that simultaneously generalises groups, equivalence relations on sets, and actions of groups on sets.

Related Topics:
Mathematics - Category theory - Homotopy theory - Heinrich Brandt - 1926 - Group - Equivalence relation - Set - Action

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They are often used to capture information about geometrical objects such as manifolds.

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