Depth-first search. Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. One starts at the root (selecting some arbitrary node as the root in the case of a graph) and explores as far as possible along each branch before backtracking.
Derivative classification is: the incorporating, paraphrasing, restating, or generating in new form information that is already classified and the marking of the new material consistent with the classification of the source material, or the marking of the information in accordance with an authorized classification guide.
Derivatives are contracts that originated from the need to limit risk. For a better conceptual understanding of different kind of derivatives, you can see this link. Derivative contracts can be standardized and traded on the stock exchange. Such derivatives are called exchange-traded derivatives. Or they can be customised as per the needs of the user by negotiating with the other party involved. Such derivatives are called over-the-counter (OTC) derivatives. A Derivative includes: (a) a security derived from a debt instrument, share, loan, whether secured or unsecured, risk instrument or contract for differences or any other form of security ;