Mathematical structure

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In mathematics, a structure is a set provided with some additional features on the set (e.g. an operation, relation, metric, or topology). Often, the additional features are attached or related to the set, so as to provide it with some additional meaning or significance.

Contents

A partial list of possible structures are measures, algebraic structures (groups, fields, etc.), topologies, metric structures (geometries), orders, graphs, events, equivalence relations, differential structures, and categories.

Sometimes, a set is endowed with more than one feature simultaneously, which allows mathematicians to study the interaction between the different structures more richly. For example, an ordering imposes a rigid form, shape, or topology on the set, and if a set has both a topology feature and a group feature, such that these two features are related in a certain way, then the structure becomes a topological group. [1]

Mappings between sets which preserve structures (i.e., structures in the domain are mapped to equivalent structures in the codomain) are of special interest in many fields of mathematics. Examples are homomorphisms, which preserve algebraic structures; homeomorphisms, which preserve topological structures; [2] and diffeomorphisms, which preserve differential structures.

History

In 1939, the French group with the pseudonym Nicolas Bourbaki saw structures as the root of mathematics. They first mentioned them in their "Fascicule" of Theory of Sets and expanded it into Chapter IV of the 1957 edition. [3] They identified three mother structures: algebraic, topological, and order. [3] [4]

Example: the real numbers

The set of real numbers has several standard structures:

There are interfaces among these:

See also

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References

  1. Saunders, Mac Lane (1996). "Structure in Mathematics" (PDF). Philosoph1A Mathemat1Ca. 4 (3): 176.
  2. Christiansen, Jacob Stordal (2015). "Mathematical structures" (PDF). maths.lth.se. Retrieved 2019-12-09.
  3. 1 2 Corry, Leo (September 1992). "Nicolas Bourbaki and the concept of mathematical structure". Synthese. 92 (3): 315–348. doi:10.1007/bf00414286. JSTOR   20117057. S2CID   16981077.
  4. Wells, Richard B. (2010). Biological signal processing and computational neuroscience (PDF). pp. 296–335. Retrieved 7 April 2016.

Further reading