# Logic characteristics of binary relations

The concept of function is defined as a special kind of binary relation. Set Theory and the Continuum Problem. Despite their simplicity, binary relations are at the core of an abstract computation model known as an abstract rewriting system. Mathematical Foundations of Computational Engineering:

Logic characteristics of binary relations characterization of difunctional relations, which also explains their name, is to consider two functions f: Thus the first element of R is the set of objects, the second is the set of persons, and the last element is a set of ordered pairs of the form object, owner. Mathematical Foundations of Computational Engineering:

For the theoretical explanation see Relation algebra. In mathematicsa binary relation on a set A is a collection of ordered pairs of elements of A. This source refers to asymmetric relations as "strictly antisymmetric".

Either approach is adequate for most uses, provided that one attends to the necessary logic characteristics of binary relations in language, notation, and the definitions of concepts logic characteristics of binary relations restrictionscompositioninverse relationand so on. For a more general notion of relation, see finitary relation. The concept of function is defined as a special kind of binary relation. This extension is needed for, among other things, modeling the concepts of "is an element of" or "is a subset of" in set theorywithout running into logical inconsistencies such as Russell's paradox.

Binary relations are used in many branches of mathematics to model concepts like " is greater than ", " is equal to ", and "divides" in arithmetic logic characteristics of binary relations, " is congruent to " in geometry"is adjacent to" in graph theory"is orthogonal to" in linear algebra and many more. Thus the first element of R is the set of objects, the second is the set of persons, and the last element is a set of ordered pairs of the form object, owner. For other uses, see Relation disambiguation. An example is the " divides " relation between the set of prime numbers P and logic characteristics of binary relations set of integers Zin which every prime p is associated with every integer z that is a multiple of p but with no integer that is not a multiple of p. A special case of this difference in points of view applies to the notion of function.

Misleading articles Articles to be expanded from April All articles to be expanded Articles using small message boxes Pages using div col without cols and colwidth parameters. Thus, a single "rule," like mapping every real number x to x logic characteristics of binary relationscan lead to distinct functions f: This section may contain misleading parts.

Encyclopedia of Optimization 2nd ed. For example, restricting the relation " x is parent of y " to females yields the relation " x is mother logic characteristics of binary relations the woman y "; its transitive closure doesn't relate a woman with her paternal grandmother. Retrieved 18 November The order of the elements in each pair of G is important:

It should not be confused with relation al algebra which deals in finitary relations and in practice also finite and many-sorted. A Categorical Approach to L-fuzzy Relations. The choice between the two definitions usually matters only in very formal contexts, like category theory.

Also, the various logic characteristics of binary relations of completeness not to be confused with being "total" do not carry over to restrictions. On the other hand, the transitive closure of "is parent of" is "is ancestor of"; its restriction to females does relate a woman with her paternal grandmother. This source refers to asymmetric relations as "strictly antisymmetric". From Maybe Functions to Hash Tables. Pahl; Rudolf Damrath