# completeness

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**Worse is better**— Worse is better, also called the New Jersey style, was conceived by Richard P. Gabriel to describe the dynamics of software acceptance, but it has broader application. The idea is that quality does not necessarily increase with functionality.… …72

**Lattice (order)**— See also: Lattice (group) The name lattice is suggested by the form of the Hasse diagram depicting it. Shown here is the lattice of partitions of a four element set {1,2,3,4}, ordered by the relation is a refinement of . In mathematics, a… …73

**Semilattice**— In mathematics, a join semilattice (or upper semilattice) is a partially ordered set which has a join (a least upper bound) for any nonempty finite subset. Dually, a meet semilattice (or lower semilattice) is a partially ordered set which has a… …74

**Theory (mathematical logic)**— This article is about theories in a formal language, as studied in mathematical logic. For other uses, see Theory (disambiguation). In mathematical logic, a theory (also called a formal theory) is a set of sentences in a formal language. Usually… …75

**P versus NP problem**— Unsolved problems in computer science Is P = NP ? …76

**Least-upper-bound property**— In mathematics, the least upper bound property is a fundamental property of the real numbers and certain other ordered sets. The property states that any non empty set of real numbers that has an upper bound necessarily has a least upper bound… …77

**Numerical 3-dimensional matching**— is a strongly NP complete decision problem. It is given by three multisets of integers X, Y and Z, each containing k elements, and a bound b. The goal is to select a subset M of such that every integer in X, Y and Z occurs exactly once and that… …78

**Outline of logic**— The following outline is provided as an overview of and topical guide to logic: Logic – formal science of using reason, considered a branch of both philosophy and mathematics. Logic investigates and classifies the structure of statements and… …79

**Probabilistically checkable proof**— In computational complexity theory, a probabilistically checkable proof (PCP) is a type of proof that can be checked by a randomized algorithm using a bounded amount of randomness and reading a bounded number of bits of the proof. The algorithm… …80

**Cauchy sequence**— In mathematics, a Cauchy sequence, named after Augustin Cauchy, is a sequence whose elements become arbitrarily close to each other as the sequence progresses. To be more precise, by dropping enough (but still only a finite number of) terms from… …