Flatness (mathematics)

In mathematics, the flatness (symbol: ⏥) of a surface is the degree to which it approximates a mathematical plane. The term is often generalized for higher-dimensional manifolds to describe the degree to which they approximate the Euclidean space of the same dimensionality. (See curvature.)^[1]

Flatness in homological algebra and algebraic geometry means, of an object $A$ in an abelian category, that $-\otimes A$ is an exact functor. See flat module or, for more generality, flat morphism.^[2]

Character encodings

Character information
Preview	⏥
Unicode name	FLATNESS
Encodings	decimal	hex
Unicode	9189	U+23E5
UTF-8	226 143 165	E2 8F A5
Numeric character reference	⏥	⏥

References

^ Committee 117, A. C. I. (November 3, 2006). Specifications for Tolerances for Concrete Construction and Materials and Commentary. American Concrete Institute. ISBN 9780870312212 – via Google Books.{{cite book}}: CS1 maint: numeric names: authors list (link)
^ Ballast, David Kent (March 16, 2007). Handbook of Construction Tolerances. John Wiley & Sons. ISBN 9780471931515 – via Google Books.

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[1] Committee 117, A. C. I. (November 3, 2006). Specifications for Tolerances for Concrete Construction and Materials and Commentary. American Concrete Institute. ISBN 9780870312212 – via Google Books.{{cite book}}: CS1 maint: numeric names: authors list (link)

[2] Ballast, David Kent (March 16, 2007). Handbook of Construction Tolerances. John Wiley & Sons. ISBN 9780471931515 – via Google Books.

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