A **mathematical object** is an abstract concept arising in mathematics.
In usual language of mathematics, an *object* is anything that has been (or could be) formally defined, and with which one may do deductive reasoning and mathematical proofs. Typically, a mathematical object can be the value of a variable, and therefore can be involved in formulas. Commonly encountered mathematical objects include: numbers, integers, integer partition, or expressions. Each branch of mathematics has its own objects. Some examples are:

- Geometry
- points, lines, line segments,
- polygons (triangles, squares, pentagons, hexagons, ...), circles, ellipses, parabolas, hyperbolas,
- polyhedra (tetrahedrons, cubes, octahedrons, dodecahedrons, icosahedrons, ), spheres, ellipsoids, paraboloids, hyperboloids, cylinders, cones.

Categories are simultaneously homes to mathematical objects and mathematical objects in their own right. In proof theory, proofs and theorems are also mathematical objects.

The ontological status of mathematical objects has been the subject of much investigation and debate by philosophers of mathematics.^{[1]}

## See also

## References

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (June 2009) (Learn how and when to remove this template message) |

**^**Burgess, John, and Rosen, Gideon, 1997.*A Subject with No Object: Strategies for Nominalistic Reconstrual of Mathematics*. Oxford University Press. ISBN 0198236158

- Azzouni, J., 1994.
*Metaphysical Myths, Mathematical Practice*. Cambridge University Press. - Burgess, John, and Rosen, Gideon, 1997.
*A Subject with No Object*. Oxford Univ. Press. - Davis, Philip and Reuben Hersh, 1999 [1981].
*The Mathematical Experience*. Mariner Books: 156–62. - Gold, Bonnie, and Simons, Roger A., 2011.
*Proof and Other Dilemmas: Mathematics and Philosophy*. Mathematical Association of America. - Hersh, Reuben, 1997.
*What is Mathematics, Really?*Oxford University Press. - Sfard, A., 2000, "Symbolizing mathematical reality into being, Or how mathematical discourse and mathematical objects create each other," in Cobb, P.,
*et al.*,*Symbolizing and communicating in mathematics classrooms: Perspectives on discourse, tools and instructional design*. Lawrence Erlbaum. - Stewart Shapiro, 2000.
*Thinking about mathematics: The philosophy of mathematics*. Oxford University Press.

## External links

- Stanford Encyclopedia of Philosophy: "Abstract Objects"—by Gideon Rosen.
- Wells, Charles, "Mathematical Objects."
- AMOF: The Amazing Mathematical Object Factory
- Mathematical Object Exhibit