Inversjon

Inversjon, or inversion in English, is a general term for reversing order, orientation, or relationship within a system. It describes a change from a normal or expected arrangement to an opposite or mirrored one, and its precise meaning depends on the discipline.

In linguistics, inversion refers to placing elements in an order different from the ordinary subject–verb sequence, typically to form questions or to emphasize a component. English questions often use auxiliary inversion, as in Are you coming? Some languages show similar patterns in other grammatical contexts, affecting word order rather than semantics.

In mathematics and logic, an inverse operation or inverse function undoes the effect of another operation. If f(x) = y, then applying the inverse function f⁻¹ to y yields x. Examples include the reciprocal 1/x as the inverse of multiplication by x, and subtraction as the inverse of addition. Inverse relations satisfy the property that composing a function with its inverse returns the original input.

In chemistry and stereochemistry, Walden inversion describes the change in configuration at a stereogenic center during certain nucleophilic substitutions, notably SN2 reactions. The product has the opposite absolute configuration at the reactive center compared with the starting material.

In music theory, inversion refers to reordering the notes of a chord or melody so that a different note assumes the bass. A triad in root position C–E–G can appear in first inversion E–G–C or second inversion G–C–E, altering the sonority without changing the chord’s identity.

In other contexts, inversion can also describe color inversion in imaging (creating negative images), or inversion symmetries in physics and geometry, where spatial properties are mirrored.