nonzero element
31Complete Boolean algebra — This article is about a type of mathematical structure. For complete sets of Boolean operators, see Functional completeness. In mathematics, a complete Boolean algebra is a Boolean algebra in which every subset has a supremum (least upper bound) …
32Glossary of field theory — Field theory is the branch of mathematics in which fields are studied. This is a glossary of some terms of the subject. (See field theory (physics) for the unrelated field theories in physics.) Definition of a field A field is a commutative ring… …
33Stiefel–Whitney class — In mathematics, the Stiefel–Whitney class arises as a type of characteristic class associated to real vector bundles E ightarrow X. It is denoted by w ( E ), taking values in H^*(X; /2), the cohomology groups with mod 2 coefficients. The… …
34Covering graph — In the mathematical discipline of graph theory, a graph C is a covering graph of another graph G if there is a covering map from the vertex set of C to the vertex set of G. A covering map f is a surjection and a local isomorphism: the… …
35Hasse norm theorem — In number theory, the Hasse norm theorem states that if L/K is a cyclic extension of number fields, then if a nonzero element of K is a local norm everywhere, then it is a global norm.Here to be a global norm means to be an element k of K such… …
36Orientation (mathematics) — See also orientation (geometry). In mathematics, an orientation on a real vector space is a choice of which ordered bases are positively oriented and which are negatively oriented. In the three dimensional Euclidean space, the two possible basis… …
37Cyclic module — In mathematics, more specifically in ring theory, a cyclic module is a module over a ring which is generated by one element. The term is by analogy with cyclic groups, that is groups which are generated by one element. Contents 1 Definition 2… …
38Divisibility (ring theory) — In mathematics, the notion of a divisor originally arose within the context of arithmetic of whole numbers. Please see the page about divisors for this simplest example. With the development of abstract rings, of which the integers are the… …
39Norm of an ideal — The norm of an ideal is defined in algebraic number theory. Let Ksubset L be two number fields with rings of integers O Ksubset O L. Suppose that the extension L/K is a Galois extension with :G= extstyle{Gal}(L/K). The norm of an ideal I of O L… …
40Systolic geometry — In mathematics, systolic geometry is the study of systolic invariants of manifolds and polyhedra, as initially conceived by Charles Loewner, and developed by Mikhail Gromov and others, in its arithmetic, ergodic, and topological manifestations.… …
