Helyettesítés

Helyettesítés is the act of replacing one element with another. The term is used across disciplines to describe a replacement process that maintains the continuity or function of a system.

In mathematics, helyettesítés refers to the substitution method for solving systems of equations. One equation is solved for one variable; that expression is substituted into the other equations, progressively eliminating variables until the solution is reached. The method is commonly taught for linear and algebraic systems and can also describe substitution within expressions or function definitions.

In chemistry, helyettesítés (helyettesítő reakció) denotes substitution reactions, where an atom or group in a molecule is replaced by another atom or group. These are common in organic chemistry and may proceed via radical or nucleophilic mechanisms, depending on conditions. An example is the replacement of a hydrogen atom in methane by a halogen to form chloromethane and hydrogen chloride.

In linguistics and computing, helyettesítés covers substituting words or symbols with others, such as replacing pronouns for explicit nouns, or performing text substitution in editing or templating. In cryptography, substitution ciphers replace each element of plaintext with another symbol according to a rule.

In social and organizational contexts, helyettesítés can mean acting in the place of a colleague or manager during absence, or filling a temporary position.