BarterIn trade, barter (derived from baretor) is a system of exchange in which participants in a transaction directly exchange goods or services for other goods or services without using a medium of exchange, such as money. Economists usually distinguish barter from gift economies in many ways; barter, for example, features immediate reciprocal exchange, not one delayed in time. Barter usually takes place on a bilateral basis, but may be multilateral (if it is mediated through a trade exchange).
Medium of exchangeIn economics, a medium of exchange is any item that is widely acceptable in exchange for goods and services. In modern economies, the most commonly used medium of exchange is currency. The origin of "mediums of exchange" in human societies is assumed to have arisen in antiquity as awareness grew of the limitations of barter. The form of the "medium of exchange" follows that of a token, which has been further refined as money. A "medium of exchange" is considered one of the functions of money.
Matching (graph theory)In the mathematical discipline of graph theory, a matching or independent edge set in an undirected graph is a set of edges without common vertices. In other words, a subset of the edges is a matching if each vertex appears in at most one edge of that matching. Finding a matching in a bipartite graph can be treated as a network flow problem. Given a graph G = (V, E), a matching M in G is a set of pairwise non-adjacent edges, none of which are loops; that is, no two edges share common vertices.
Matrix decompositionIn the mathematical discipline of linear algebra, a matrix decomposition or matrix factorization is a factorization of a matrix into a product of matrices. There are many different matrix decompositions; each finds use among a particular class of problems. In numerical analysis, different decompositions are used to implement efficient matrix algorithms. For instance, when solving a system of linear equations , the matrix A can be decomposed via the LU decomposition.
History of moneyThe history of money is the development over time of systems for the exchange, storage, and measurement of wealth. Money is a means of fulfilling these functions indirectly and in general rather than directly, as with barter. Money may take a physical form as in coins and notes, or may exist as a written or electronic account. It may have intrinsic value (commodity money), or be legally exchangeable for something with intrinsic value (representative money), or only have nominal value (fiat money).
Social networkA social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and examine network dynamics.
Collaborative consumptionCollaborative consumption is the set of those resource circulation systems in which consumers both "obtain" and "provide", temporarily or permanently, valuable resources or services through direct interaction with other consumers or through a mediator. It is sometimes paired with the concept of the "sharing economy". Collaborative consumption is not new; it has always existed (e.g. in the form of flea markets, swap meets, garage sales, car boot sales, and second-hand shops).
Blossom algorithmIn graph theory, the blossom algorithm is an algorithm for constructing maximum matchings on graphs. The algorithm was developed by Jack Edmonds in 1961, and published in 1965. Given a general graph G = (V, E), the algorithm finds a matching M such that each vertex in V is incident with at most one edge in M and is maximized. The matching is constructed by iteratively improving an initial empty matching along augmenting paths in the graph.
Maximum cardinality matchingMaximum cardinality matching is a fundamental problem in graph theory. We are given a graph G, and the goal is to find a matching containing as many edges as possible; that is, a maximum cardinality subset of the edges such that each vertex is adjacent to at most one edge of the subset. As each edge will cover exactly two vertices, this problem is equivalent to the task of finding a matching that covers as many vertices as possible.
Social dynamicsSocial dynamics (or sociodynamics) is the study of the behavior of groups that results from the interactions of individual group members as well to the study of the relationship between individual interactions and group level behaviors. The field of social dynamics brings together ideas from economics, sociology, social psychology, and other disciplines, and is a sub-field of complex adaptive systems or complexity science. The fundamental assumption of the field is that individuals are influenced by one another's behavior.
