Deformation retract — Retract redirects here. For other meanings including concepts in group theory and category theory, see Retraction (disambiguation). In topology, a branch of mathematics, a retraction [1], as the name suggests, retracts an entire space into a… … Wikipedia
Number theory — A Lehmer sieve an analog computer once used for finding primes and solving simple diophantine equations. Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers (the… … Wikipedia
Reduction of the structure group — In mathematics, in particular the theory of principal bundles, one can ask if a G bundle comes from a subgroup H < G. This is called reduction of the structure group (to H), and makes sense for any map H o G, which need not be an inclusion… … Wikipedia
Induced homomorphism (fundamental group) — In mathematics, especially in the area of topology known as algebraic topology, the induced homomorphism is a group homomorphism related to the study of the fundamental group.DefinitionLet X and Y be topological spaces; let x 0 be a point of X… … Wikipedia
List of mathematics articles (R) — NOTOC R R. A. Fisher Lectureship Rabdology Rabin automaton Rabin signature algorithm Rabinovich Fabrikant equations Rabinowitsch trick Racah polynomials Racah W coefficient Racetrack (game) Racks and quandles Radar chart Rademacher complexity… … Wikipedia
Retraction (disambiguation) — A retraction is a public statement made to correct a previously made statement that was incorrect, invalid, or in error.Retraction may also refer to * Deformation retract or absolute retract, subjects in mathematical topology * Retract (category… … Wikipedia
List of mathematics articles (D) — NOTOC D D distribution D module D D Agostino s K squared test D Alembert Euler condition D Alembert operator D Alembert s formula D Alembert s paradox D Alembert s principle Dagger category Dagger compact category Dagger symmetric monoidal… … Wikipedia
Seifert–van Kampen theorem — In mathematics, the Seifert–van Kampen theorem of algebraic topology, sometimes just called van Kampen s theorem, expresses the structure of the fundamental group of a topological space X, in terms of the fundamental groups of two open, path… … Wikipedia
CEP subgroup — In mathematics, in the field of group theory, a subgroup of a group is said to have the Congruence Extension Property or to be a CEP subgroup if every congruence on the subgroup lifts to a congruence of the whole group. Equivalently, every normal … Wikipedia
C normal subgroup — In mathematics, in the field of group theory, a subgroup H of a group G is called c normal if there is a normal subgroup T of G such that HT = G and the intersection of H and T lies inside the normal core of H.For a weakly c normal subgroup, we… … Wikipedia
