Extension

Extension, extend or extended may refer to:

Computing

• Extensibility
• Filename extension, suffix to the name of a computer file, designed to show its format
• Software extension, a file containing programming that serves to extend the capabilities of or data available to a more basic program
  • Extension (Mac OS), particular type of this software
  • Mozilla extensions for Firefox and other Mozilla projects
• Extends, a keyword used in some object-oriented programming languages to denote class inheritance

Mathematics

Algebra

• Abelian extension
• Algebraic extension
• Artin–Schreier extension
• Cyclotomic extension, see abelian extension
• Degree of a field extension
• Dual basis in a field extension
• Extension and contraction of ideals
• Extension of modules
• Extension problem
• Field extension
• Galois extension
• Group extension, and central extension
• Integral extension
• Kernel extension theorem
• Kummer extension
• Normal extension
• Quadratic extension
• Quadratic field extension
• Ring extension
• Separable extension
• Simple extension
• Splitting of prime ideals in Galois extensions
• Trivial extension, see field extension

Analysis

• Carathéodory's extension theorem
• Continuous linear extension
• Hahn–Banach theorem
• Krein extension theorem
• M. Riesz extension theorem

Logic or set theory

• Axiom of extensionality
• Extensible cardinal
• Extension (model theory)
• Extension (predicate logic), the set of tuples of values that satisfy the predicate
• Extension (semantics), the set of things to which a property is applied
• Extension by definitions
• Extensional definition, a definition that enumerates every individual a term applies to
• Extensionality

Other uses

• Extension of a polyhedron, in geometry
• Exterior algebra, Grassmann's theory of extension, in geometry
• Homotopy extension property, in topology
• Kolmogorov extension theorem, in probability theory
• Linear extension, in order theory
• Sheaf extension, in algebraic geometry
• Tietze extension theorem, in topology
• Whitney extension theorem, in differential geometry

Music

• Extension (music), notes that fit outside the standard range
• Extended (Solar Fields album), 2005
• Extension (George Braith album), 1964
• Extension (Clare Fischer album), 1963
• Extensions (Ahmad Jamal album), 1965
• Extensions (McCoy Tyner album), 1970
• Extensions (Dave Holland album), 1988
• Extensions (The Manhattan Transfer album), 1979

Places

• Extension, British Columbia, a village near Regional District of Nanaimo, British Columbia, Canada
• Extension, Louisiana, unincorporated community, United States

Science

• Extension (geology), relating to the pulling apart of the Earth's crust and lithosphere
• Extension (kinesiology), movement of a joint whereby one part of the body is moved away from another
• Extension, a human anatomical term denoting movement of limb away from body
• Extension locus, the gene locus of Melanocortin 1 receptor

Other uses

• Continuing education, or extension school, a school for continuing education
• Cooperative extension service, a division of US Department of Agriculture
• Extension (metaphysics), the property of taking up space
• Extension (telephone), telephone line attached to a main line or to a PBX or Centrex system
• Extension cord, power cable with a plug on one end and one or more sockets on the other end
• Eyelash extensions, material applied to eyelashes
• Hair extensions, strands of hair added to existing hair
• Extension, the building of community capacity by outsiders, for instance agricultural extension