(mathematics) A measure of length given by "the square root of the squares." Denoted by ||·||₂, the two-norm of a vector ⃑v= is ||⃑v||₂=√. The two norm of an m⨯m matrix A is defined by max _(⃑v≠⃑0)|/} where ⃑v is an m-dimensional vector that is not the zero vector.

(mathematical analysis) A function denoted ∥v∥ that maps a vector v to a non-negative value such that ∥cv∥ = |c|.∥v∥, where c is a scalar, and ∥v + w∥ ≤ ∥v∥ + ∥w∥ (the triangle inequality); the condition that ∥v∥ = 0 implies that v = 0 is not required, but when it holds, the semi-norm is a norm.

(mathematics) A norm of an ordinary Euclidean space, for which the Pythagorean theorem holds, defined by |x|=√

(fuzzy logic) A mathematical function T: [0, 1] × [0, 1] → [0, 1] that is commutative, associative, monotonic, and the number 1 acts as identity element, that is T(a, 1) = a.

(number theory) A p-adic absolute value, for a given prime number p, the function, denoted |..|ₚ and defined on the rational numbers, such that |0|ₚ = 0 and, for x≠0, |x|ₚ = p^(-ordₚ(x)), where ordₚ(x) is the p-adic ordinal of x; the same function, extended to the p-adic numbers ℚₚ (the completion of the rational numbers with respect to the p-adic ultrametric defined by said absolute value); the same function, further extended to some extension of ℚₚ (for example, its algebraic closure).

(business) backcasting; planning ahead by starting from a future goal and working backwards through the necessary steps

(education) In the United States, the practice of adjusting test scores based on the race of the person taking the test.

plural of Gowers norm

(philosophy) A statement expressing a value judgment answering the question of what ought to be, as opposed to what there is.

(economics) economic thought in which one applies moral beliefs, or judgment, claiming that an outcome is "good" or "bad". For example: "this tax on cigarettes will be good because it will reduce smoking."