All previously mentioned.

The process of research, examination, etc., is required to prove or establish authenticity or validity.

Validation is intended to ensure a product, service, or system results in a product, service, or system that meets the operational needs of the user, validation procedures may involve modeling either flow and using simulations.

Checking the formal correctness or integrity.

An operation that, under specified conditions, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties.