Indizes

Indizes, the plural form of index in several languages, denotes a sign, measure, or reference that points to or summarizes information about a larger set of items. The term is used in mathematics, computer science, finance, linguistics, and information science, often with distinct but related meanings.

In mathematics, an index labels an element in a sequence or array, such as a_i or x_j. Indices also denote components of tensors and appear in summations and products to track variables or dimensions.

In computer science and data management, an index is a data structure that accelerates data retrieval. Database indexes and search engine inverted indices map keys or terms to records or documents, while index structures such as B-trees and hash tables optimize queries and sorting.

In finance, stock indices aggregate the values of selected assets to represent market performance. Indices can be price-weighted or market-cap weighted and are used as benchmarks, performance measures, or investment products. They are constructed with inclusion rules and can be rebalanced over time.

In linguistics and semiotics, an index is a sign that points to its referent through contextual connection, including deictic expressions like this and that, or temporal and spatial markers.

In publishing and information organization, an index lists topics, names, and terms with page references to aid navigation.

Indizes thus function as tools for reference, comparison, and navigation across systems of data and meaning, helping users access information efficiently.