- •1 Discrete mathematics
- •103 Structure (mathematical logic)
- •17 2.6 Graph theory
- •12 2.1 Theoretical computer science
- •36 Computational geometry has been an important part of the computer graphics incorporated into modern video games and computer-aided design tools.
- •42 Complexity studies the time taken by algorithms, such as this sorting routine.
- •46 The ascii codes for the word "Wikipedia", given here in binary, provide a way of representing the word in information theory, as well as for information-processing algorithms.
- •74 Main article: finite difference
- •105 In universal algebra and in model theory, a structure consists of a set along with a collection of finitary operations and relations which are defined on it.
- •105 In universal algebra and in model theory, a structure consists of a set along with a collection of finitary operations and relations which are defined on it.
- •25 2.14 Game theory, decision theory, utility theory, social choice theory
- •25 2.14 Game theory, decision theory, utility theory, social choice theory
- •32 Much research in graph theory was motivated by attempts to prove that all maps, like this one, could be colored with only four colors. Kenneth Appel and Wolfgang Haken finally proved this in 1976.
- •8 Although the main objects of study in discrete mathematics are discrete objects, analytic methods from continuous mathematics are often employed as well.
- •8 Although the main objects of study in discrete mathematics are discrete objects, analytic methods from continuous mathematics are often employed as well.
- •32 Much research in graph theory was motivated by attempts to prove that all maps, like this one, could be colored with only four colors. Kenneth Appel and Wolfgang Haken finally proved this in 1976.
- •25 2.14 Game theory, decision theory, utility theory, social choice theory
- •115 2 Induced substructures and closed subsets
- •25 2.14 Game theory, decision theory, utility theory, social choice theory
- •36 Computational geometry has been an important part of the computer graphics incorporated into modern video games and computer-aided design tools.
- •28 2.17 Hybrid discrete and continuous mathematics
- •61 Graph theory has close links to group theory. This truncated tetrahedron graph is related to the alternating group a4.
- •32 Much research in graph theory was motivated by attempts to prove that all maps, like this one, could be colored with only four colors. Kenneth Appel and Wolfgang Haken finally proved this in 1976.
- •162 Is called an (induced) substructure of if
- •25 2.14 Game theory, decision theory, utility theory, social choice theory
- •77 Computational geometry applies computer algorithms to representations of geometrical objects.
- •90 Payoff matrix for the Prisoner's dilemma, a common example in game theory. One player chooses a row, the other a column; the resulting pair gives their payoffs
- •67 The Ulam spiral of numbers, with black pixels showing prime numbers. This diagram hints at patterns in the distribution of prime numbers.
25 2.14 Game theory, decision theory, utility theory, social choice theory
86 Game theory, decision theory, utility theory, social choice theory
91 Decision theory is concerned with identifying the values, uncertainties and other issues relevant in a given decision, its rationality, and the resulting optimal decision.
defined
75 A function defined on an interval of the integers is usually called a sequence. A sequence could be a finite sequence from some data source or an infinite sequence from a discrete dynamical system. Such a discrete function could be defined explicitly by a list (if its domain is finite), or by a formula for its general term, or it could be given implicitly by a recurrence relation or difference equation. Difference equations are similar to a differential equations, but replace differentiation by taking the difference between adjacent terms; they can be used to approximate differential equations or (more often) studied in their own right. Many questions and methods concerning differential equations have counterparts for difference equations. For instance where there are integral transforms in harmonic analysis for studying continuous functions or analog signals, there are discrete transforms for discrete functions or digital signals. As well as the discrete metric there are more general discrete or finite metric spaces and finite topological spaces.
105 In universal algebra and in model theory, a structure consists of a set along with a collection of finitary operations and relations which are defined on it.
138 Formally, a structure can be defined as a triple consisting of a domain A, a signature ?, and an interpretation function I that indicates how the signature is to be interpreted on the domain. To indicate that a structure has a particular signature ? one can refer to it as a ?-structure.
157 and and are similarly defined.
elements
150 The standard signature ?f for fields consists of two binary function symbols + and ?, a unary function symbol ?, and the two constant symbols 0 and 1. Thus a structure (algebra) for this signature consists of a set of elements A together with two binary functions, a unary function, and two distinguished elements; but there is no requirement that it satisfy any of the field axioms. The rational numbers Q, the real numbers R and the complex numbers C, like any other field, can be regarded as ?-structures in an obvious way:
160 The ordinary signature for set theory includes a single binary relation ?. A structure for this signature consists of a set of elements and an interpretation of the ? relation as a binary relation on these elements.
167 A subset of the domain of a structure is called closed if it is closed under the functions of , i.e. if the following condition is satisfied: for every natural number n, every n-ary function symbol f (in the signature of ) and all elements , the result of applying f to the n-tuple is again an element of B: .
examples
72 Algebraic structures occur as both discrete examples and continuous examples. Discrete algebras include: boolean algebra used in logic gates and programming; relational algebra used in databases; discrete and finite versions of groups, rings and fields are important in algebraic coding theory; discrete semigroups and monoids appear in the theory of formal languages.
114 1.4 Examples
116 2.1 Examples
149 Examples
f
147 The interpretation function I of assigns functions and relations to the symbols of the signature. Each function symbol f of arity n is assigned an n-ary function on the domain. Each relation symbol R of arity n is assigned an n-ary relation on the domain. A nullary function symbol c is called a constant symbol, because its interpretation I(c) can be identified with a constant element of the domain.
148 When a structure (and hence an interpretation function) is given by context, no notational distinction is made between a symbol s and its interpretation I(s). For example if f is a binary function symbol of , one simply writes rather than .
150 The standard signature ?f for fields consists of two binary function symbols + and ?, a unary function symbol ?, and the two constant symbols 0 and 1. Thus a structure (algebra) for this signature consists of a set of elements A together with two binary functions, a unary function, and two distinguished elements; but there is no requirement that it satisfy any of the field axioms. The rational numbers Q, the real numbers R and the complex numbers C, like any other field, can be regarded as ?-structures in an obvious way:
167 A subset of the domain of a structure is called closed if it is closed under the functions of , i.e. if the following condition is satisfied: for every natural number n, every n-ary function symbol f (in the signature of ) and all elements , the result of applying f to the n-tuple is again an element of B: .
game