Deluttryck

Deluttryck, or subexpression in English, denotes an expression that occurs as a part of a larger expression and, when evaluated, contributes to the value of the surrounding expression. Subexpressions can be simple constants or variables, or more complex expressions themselves, and they may be nested within each other.

In mathematics, subexpressions appear in almost every expression. For example, in (a + b)^2, the subexpression a + b forms part of the larger expression, and in 3x + 5 the terms 3x and 5 are subexpressions. Subexpressions can be nested indefinitely, and identifying them is important for parsing, simplification, and evaluation.

In computer science, subexpressions are central to programming languages. They are the parts of an expression that are evaluated to produce a value used by the surrounding expression. For example, in (x + y) * z, (x + y) is a subexpression; within it, x and y are also subexpressions. The notion helps compilers build abstract syntax trees and manage evaluation order, side effects, and optimizations.

In formal logic and linguistics, subexpressions or subformulas and subphrases respectively refer to smaller units within a larger expression or sentence. Recognizing subexpressions supports systematic reasoning, rule application, and syntactic analysis.

Deluttryck is a general term across domains; in Swedish texts it is commonly used to refer to such components. See also subexpression, subformula, operand, and abstract syntax tree.