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Antichain — In mathematics, in the area of order theory, an antichain is a subset of a partially ordered set such that any two elements in the subset are incomparable. (Some authors use the term antichain to mean strong antichain, a subset such that there is … Wikipedia
Strong antichain — In order theory, a subset A of a partially ordered set X is said to be a strong downwards antichain if no two elements have a common lower bound, that is,:forall x, y in A mbox{such that } x ot= y otexists z x geq z and y geq z. A strong upwards… … Wikipedia
Dilworth's theorem — In mathematics, in the areas of order theory and combinatorics, Dilworth s theorem characterizes the width of any finite partially ordered set in terms of a partition of the order into a minimum number of chains. It is named for the mathematician … Wikipedia
Dedekind number — … Wikipedia
Forcing (mathematics) — For the use of forcing in recursion theory, see Forcing (recursion theory). In the mathematical discipline of set theory, forcing is a technique invented by Paul Cohen for proving consistency and independence results. It was first used, in 1963,… … Wikipedia
Countable chain condition — See also: Forcing (set theory)#The countable chain condition In order theory, a partially ordered set X is said to satisfy the countable chain condition, or to be ccc, if every strong antichain in X is countable. There are really two conditions:… … Wikipedia
Dedekind–MacNeille completion — The Hasse diagram of a partially ordered set (left) and its Dedekind–MacNeille completion (right). In order theoretic mathematics, the Dedekind–MacNeille completion of a partially ordered set (also called the completion by cuts or normal… … Wikipedia
Mathematical jargon — The language of mathematics has a vast vocabulary of specialist and technical terms. It also has a certain amount of jargon: commonly used phrases which are part of the culture of mathematics, rather than of the subject. Jargon often appears in… … Wikipedia
Abouabdillah's theorem — refers to two distinct theorems in mathematics: one in geometry and one in number theory.GeometryIn geometry, similarities of an Euclidean space preserve circles and spheres. Conversely, Abouabdillah s theorem states that every injective or… … Wikipedia
Driss Abouabdillah — ( ar. ادريس أبو عبدالله) (or Driss Bouabdillah) is a Moroccan mathematician born in Meknès on April 1, 1948. He is a former teacher of mathematics at the ENS (higher teacher training school) of Rabat. Contributions *In geometry, he gave several… … Wikipedia
