set of rational numbers
71Age (model theory) — In model theory, a branch of mathematical logic, the age of a structure (or model) A is the class of all finitely generated structures which are embeddable in A (i.e. isomorphic to substructures of A ). This concept is central in the construction …
72Saturated model — There is an unrelated notion of saturated model in the context of structural equation modeling. In mathematical logic, and particularly in its subfield model theory, a saturated model M is one which realizes as many complete types as may be… …
73Tonality diamond — In music theory, the n limit tonality diamond is the set of rational numbers r, 1 le r < 2, such that the odd part of both the numerator and the denominator of r, when reduced to lowest terms, is less than or equal to the fixed odd number n.… …
74Almost disjoint sets — In mathematics, two sets are almost disjoint if their intersection is small in some sense. Different definitions of small will therefore result in different definitions of almost disjoint . Definition The most common choice is to take small to… …
75Morley rank — In mathematical logic, Morley rank, introduced by Michael D. Morley (1965), is a means of measuring the size of a subset of a model of a theory, generalizing the notion of dimension in algebraic geometry. Contents 1 Definition 2 Examples 3… …
76Stark–Heegner theorem — In number theory, a branch of mathematics, the Stark–Heegner theorem states precisely which quadratic imaginary number fields admit unique factorisation in their ring of integers. It solves a special case of Gauss s class number problem of… …
77dense — adjective (denser; densest) Etymology: Latin densus; akin to Greek dasys thick with hair or leaves Date: 15th century 1. a. marked by compactness or crowding together of parts < dense vegetation > < dense traffic > …
78mathematics — /math euh mat iks/, n. 1. (used with a sing. v.) the systematic treatment of magnitude, relationships between figures and forms, and relations between quantities expressed symbolically. 2. (used with a sing. or pl. v.) mathematical procedures,… …
79Number — For other uses, see Numbers (disambiguation). A number is a mathematical object used to count and measure. In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational… …
80Logic and the philosophy of mathematics in the nineteenth century — John Stillwell INTRODUCTION In its history of over two thousand years, mathematics has seldom been disturbed by philosophical disputes. Ever since Plato, who is said to have put the slogan ‘Let no one who is not a geometer enter here’ over the… …
