Residue (redirected from residue avoidance)

residue

Law what is left of an estate after the discharge of debts and distribution of specific gifts

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residue [′rez·ə‚dü]

(chemical engineering)

The substance left after distilling off all but the heaviest components from crude oil in petroleum refinery operations. Also known as bottoms; residuum.

Solids deposited onto the filter medium during filtration. Also known as cake; discharged solids.

(geology)

The in-place accumulation of rock debris which remains after weathering has removed all but the least soluble constituent.

(mathematics)

The residue of a complex function ƒ(z) at an isolated singularityz₀is given by (1/2πi) ∫ ƒ(z)dzalong a simple closed curve interior to an annulus aboutz₀; equivalently, the coefficient of the term (z-z₀)^-1in the Laurent series expansion of ƒ(z) aboutz₀.

In general, a coset of an ideal in a ring.

A residue ofmof ordern, wheremandnare integers, is a remainder that results from raising some integer to thenth power and dividing bym.

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Residue 

(1) In the theory of numbers, number a is the residue of number b modulo m if the difference a — b is divisible by m (a, b, and m > 0 are integers). For example, the number 24 is the residue of the number 3 modulo 7, since 24 - 3 is divisible by 7. The set of m integers, each of which is the residue of one and only one of the numbers 0, 1, . . . , m—1, is said to be a complete residue system modulo m. For example, the numbers 1, 6, 11, 16, 21, 26 form the complete residue system modulo 6. The number a is called a residue of order n (n≥ 2—an integer) modulo m if there exists an integer x such that the difference xⁿ - a is divisible by m. If this is not the case, then a is called a nonresidue of order n. For example, 2 and 3 are a residue and a nonresidue of the second order (quadratics) modulo 7.

REFERENCE

Vinogradov, I. M. Osnovy teorii chisel, 7th ed. Moscow, 1965.

A. A. KARATSUBA

(2) In the theory of analytic functions, the residue of a single-valued analytic function f(z) at an isolated singular point Z₀ is the coefficient of (z - Z₀)^—1 in the expansion of f(z) in a series of powers of z - Z₀ (Laurent series) valid in a neighborhood of Z₀. The notation used is f(z). If Y is a circle with center at Z₀ and sufficiently small radius (a circle so small that within it the function f(z) has no singular points other than Z₀), then

The importance of residues stems from the following theorem. Let f(Z) be a single-valued function analytic in a domain D, with the exception of isolated singular points, and let G be a simple closed rectifiable curve belonging to domain D together with its interior and not passing through the singular points of f(z); if Z₁, . . . , z_n are all the singular points of f(z) lying within G, then

Since it is relatively simple to calculate residues, this theorem is an effective means for evaluating integrals.

A. A. GONCHAR