two-letter matrix
51Computer keyboard — A key being pressed on a computer keyboard. In computing, a keyboard is a typewriter style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper… …
52Bernoulli number — In mathematics, the Bernoulli numbers Bn are a sequence of rational numbers with deep connections to number theory. They are closely related to the values of the Riemann zeta function at negative integers. There are several conventions for… …
53Substitution cipher — In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters,… …
54Doomsday rule — John Conway, inventor of the Doomsday algorithm The Doomsday rule or Doomsday algorithm is a way of calculating the day of the week of a given date. It provides a perpetual calendar since the Gregorian calendar moves in cycles of 400 years. This… …
55computer — computerlike, adj. /keuhm pyooh teuhr/, n. 1. Also called processor. an electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations. Cf. analog… …
56Dynkin diagram — See also: Coxeter–Dynkin diagram Finite Dynkin diagrams Affine (extended) Dynkin diagrams …
57Quantitative comparative linguistics — is a branch of comparative linguistics that applies mathematical models to the problem of classifying language relatedness. This includes the use of computational phylogenetics and cladistics to define an optimal tree (or network) to represent a… …
58Function (mathematics) — f(x) redirects here. For the band, see f(x) (band). Graph of example function, In mathematics, a function associates one quantity, the a …
59Index of coincidence — In cryptography, coincidence counting is the technique (invented by William F. Friedman[1]) of putting two texts side by side and counting the number of times that identical letters appear in the same position in both texts. This count, either as …
60Damerau–Levenshtein distance — In information theory and computer science, the Damerau–Levenshtein distance (named after Frederick J. Damerau and Vladimir I. Levenshtein) is a distance (string metric) between two strings, i.e., finite sequence of symbols, given by counting the …
