Let D denote the open unit disc in the complex plane .

Let D denote the open unit disc in the complex plane .

In particular, this leads to the characterization of the automorphisms of the unit disc.

In this paper he constructed a function which is analytic on the unit disk, is infinitely differentiable on the closed disk, but has no analytic continuation outside the disk.

1 The open unit disk, the plane, and the upper half-plane

This series converges to uniformly on the closed unit disc.

be the Poincaré disk in the complex plane with Poincaré metric

In the complex plane, the Poisson kernel for the unit disc is given by

IBM introduced the first disk storage unit, the IBM 350 RAMAC (Random Access Method of Accounting and Control) in 1956.

In particular, the Poisson kernel is commonly used to demonstrate the equivalence of the Hardy spaces on the unit disk, and the unit circle.

In mathematics, the Zernike polynomials are a sequence of polynomials that are orthogonal on the unit disk.

The Zernike polynomials are a set of functions that are orthogonal over the unit circle.

For example, Zernike polynomials are orthogonal on the unit disk.

The frequency converter is mainly composed of rectification (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, and detection unit micro processing unit.

The converter is mainly composed of rectifier (AC variable DC), filter, inverter (DC AC), brake unit, drive unit, detection unit micro processing unit and so on.