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Theorem

Liouville's Theorem (Complex Analysis)

Analysis

Every bounded entire function, meaning a function holomorphic on the whole complex plane, is constant. Named for Joseph Liouville, it gives a short proof of the fundamental theorem of algebra and is a basic fact about the rigidity of holomorphic functions.

Facts
Statement
Every bounded entire function on the complex plane must be constant; equivalently, a non-constant holomorphic function on all of C has an unbounded image. 1
Proof Year
1844 1
Attribution question, not yet a formal Dissent: the theorem is named for Joseph Liouville, but the cited source states it was first proven by Augustin-Louis Cauchy in 1844; Liouville is credited with an independent 1847 proof of a related special case via elliptic function theory. Named as a content.Dissent candidate in this lane's report.
Classification
Statement Form
Characterization Theorem 1
Connections

In Branch

Sources
1. Liouville's Theorem (Complex Analysis) (Wikipedia)
Wikimedia Foundation
  • Lead section, opening sentence
    Liouville's theorem states that every bounded entire function must be constant.
  • Lead section, attribution and history sentence on Cauchy's 1844 proof
    the theorem was first proven by Cauchy in 1844
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