algebraic unit
61Homotopy groups of spheres — In the mathematical field of algebraic topology, the homotopy groups of spheres describe how spheres of various dimensions can wrap around each other. They are examples of topological invariants, which reflect, in algebraic terms, the structure… …
62Perron–Frobenius theorem — In linear algebra, the Perron–Frobenius theorem, proved by Oskar Perron (1907) and Georg Frobenius (1912), asserts that a real square matrix with positive entries has a unique largest real eigenvalue and that the corresponding… …
63Roman letters used in mathematics — NOTOC Many Roman letters, both capital and small, are used in mathematics, science and engineering to denote by convention specific or abstracted constants, variables of a certain type, units, multipliers, physical entities. Certain letters, when …
64Calculator — For mechanical precursors to the modern calculator, see mechanical calculator. For other uses, see Calculator (disambiguation). An electronic pocket calculator with a 7‑segment LCD display, that can perform basic arithmetic operations …
65Georg Cantor — Infobox Scientist name = Georg Ferdinand Ludwig Cantor image width=225px caption = birth date = birth date|1845|3|3 birth place = Saint Petersburg, Russia death date = death date and age|1918|1|6|1845|3|3 death place = Halle, Germany residence =… …
66Logarithm — The graph of the logarithm to base 2 crosses the x axis (horizontal axis) at 1 and passes through the points with coordinates (2, 1), (4, 2), and (8, 3) …
67Pell's equation — is any Diophantine equation of the form:x^2 ny^2=1,where n is a nonsquare integer and x and y are integers. Trivially, x = 1 and y = 0 always solve this equation. Lagrange proved that for any natural number n that is not a perfect square there… …
68T-norm fuzzy logics — are a family of non classical logics, informally delimited by having a semantics which takes the real unit interval [0, 1] for the system of truth values and functions called t norms for permissible interpretations of conjunction. They are mainly …
69Differential geometry of surfaces — Carl Friedrich Gauss in 1828 In mathematics, the differential geometry of surfaces deals with smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives:… …
70Matrix (mathematics) — Specific elements of a matrix are often denoted by a variable with two subscripts. For instance, a2,1 represents the element at the second row and first column of a matrix A. In mathematics, a matrix (plural matrices, or less commonly matrixes)… …
