Torus

In geometry, a torus (plural tori) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis coplanar with the circle.

Description

If the axis of revolution does not touch the circle, the surface has a ring shape and is called a torus of revolution.

Real-world examples of toroidal objects include inner tubes, swim rings, and the surface of a doughnut or bagel.

A torus should not be confused with a solid torus, which is formed by rotating a disk, rather than a circle, around an axis.

A solid torus is a torus plus the volume inside the torus.

Real-world approximations include doughnuts, vadai or vada, many lifebuoys, and O-rings.

See also

• Algebraic torus
• Angenent torus
• Annulus (mathematics)
• Clifford torus
• Complex torus
• Dupin cyclide
• Elliptic curve
• Irrational cable on a torus
• Joint European Torus
• Klein Bottle
• Loewner's torus inequality
• Maximal torus
• Period lattice
• Real projective plane
• Sphere
• Spiric section
• Surface
• Toric lens
• Toric section
• Toric variety
• Toroid
• Toroidal and poloidal
• Torus-based cryptography
• Torus knot
• Tube torus
• Umbilic torus
• Villarceau circles

External links

• Torus @ Wikipedia