Near-field (mathematics)In mathematics, a near-field is an algebraic structure similar to a division ring, except that it has only one of the two distributive laws. Alternatively, a near-field is a near-ring in which there is a multiplicative identity and every non-zero element has a multiplicative inverse. A near-field is a set together with two binary operations, (addition) and (multiplication), satisfying the following axioms: A1: is an abelian group. A2: = for all elements , , of (The associative law for multiplication).
Completely distributive latticeIn the mathematical area of order theory, a completely distributive lattice is a complete lattice in which arbitrary joins distribute over arbitrary meets. Formally, a complete lattice L is said to be completely distributive if, for any doubly indexed family {xj,k | j in J, k in Kj} of L, we have where F is the set of choice functions f choosing for each index j of J some index f(j) in Kj. Complete distributivity is a self-dual property, i.e. dualizing the above statement yields the same class of complete lattices.
Algèbre des parties d'un ensembleEn théorie des ensembles, l'ensemble des parties d'un ensemble, muni des opérations d'intersection, de réunion, et de passage au complémentaire, possède une structure d'algèbre de Boole. D'autres opérations s'en déduisent, comme la différence ensembliste et la différence symétrique. L'algèbre des parties d'un ensemble étudie l'arithmétique de ces opérations (voir l'article « Opération ensembliste » pour des opérations qui ne laissent pas stable l'ensemble des parties d'un ensemble).
PointwiseIn mathematics, the qualifier pointwise is used to indicate that a certain property is defined by considering each value of some function An important class of pointwise concepts are the pointwise operations, that is, operations defined on functions by applying the operations to function values separately for each point in the domain of definition. Important relations can also be defined pointwise.
GF(2)(also denoted , Z/2Z or ) is the finite field of two elements (GF is the initialism of Galois field, another name for finite fields). Notations Z_2 and may be encountered although they can be confused with the notation of 2-adic integers. GF(2) is the field with the smallest possible number of elements, and is unique if the additive identity and the multiplicative identity are denoted respectively 0 and 1, as usual. The elements of GF(2) may be identified with the two possible values of a bit and to the boolean values true and false.
Near-semiringIn mathematics, a near-semiring, also called a seminearring, is an algebraic structure more general than a near-ring or a semiring. Near-semirings arise naturally from functions on monoids. A near-semiring is a set S with two binary operations "+" and "·", and a constant 0 such that (S, +, 0) is a monoid (not necessarily commutative), (S, ·) is a semigroup, these structures are related by a single (right or left) distributive law, and accordingly 0 is a one-sided (right or left, respectively) absorbing element.
MéréologieLa méréologie (du grec ancien , « partie ») est la discipline philosophique qui explique ce que sont les parties, les touts et les relations qui les lient. Une partie est un élément, un constituant d’une entité, appelée un tout. Par exemple, le dossier est une partie de la chaise et le générique est une partie du film. Les relations étudiées par la méréologie peuvent être entre un tout et ses parties, ou entre des parties d’un même tout.