indexmängd
An index set is a set used to identify or refer to elements of another set. In mathematics, an index set is typically a set of numbers, often natural numbers or integers, but it can be any set. When we use an index set, we are essentially creating a mapping between the elements of the index set and the elements of the set being indexed. This mapping allows us to conveniently refer to individual elements using their corresponding index.
For example, a sequence is a function whose domain is the set of natural numbers, which serves
The concept of an index set is fundamental in many areas of mathematics, including set theory, calculus,