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Title: Minimum Modulus Principle -- from Wolfram MathWorld

Open Graph Title: Minimum Modulus Principle -- from Wolfram MathWorld

X Title: Minimum Modulus Principle -- from Wolfram MathWorld

Description: Let f be analytic on a domain U subset= C, and assume that f never vanishes. Then if there is a point z_0 in U such that |f(z_0)|<=|f(z)| for all z in U, then f is constant. Let U subset= C be a bounded domain, let f be a continuous function on the closed set U^_ that is analytic on U, and assume that f never vanishes on U^_. Then the minimum value of |f| on U^_ (which always exists) must occur on partialU. In other words, min_(U^_)|f|=min_(partialU)|f|.

Open Graph Description: Let f be analytic on a domain U subset= C, and assume that f never vanishes. Then if there is a point z_0 in U such that |f(z_0)|<=|f(z)| for all z in U, then f is constant. Let U subset= C be a bounded domain, let f be a continuous function on the closed set U^_ that is analytic on U, and assume that f never vanishes on U^_. Then the minimum value of |f| on U^_ (which always exists) must occur on partialU. In other words, min_(U^_)|f|=min_(partialU)|f|.

X Description: Let f be analytic on a domain U subset= C, and assume that f never vanishes. Then if there is a point z_0 in U such that |f(z_0)|<=|f(z)| for all z in U, then f is constant. Let U subset= C be a bounded domain, let f be a continuous function on the closed set U^_ that is analytic on U, and assume that f never vanishes on U^_. Then the minimum value of |f| on U^_ (which always exists) must occur on partialU. In other words, min_(U^_)|f|=min_(partialU)|f|.

Opengraph URL: https://mathworld.wolfram.com/MinimumModulusPrinciple.html

X: @WolframResearch

direct link

Domain: mathworld.wolfram.com

DC.TitleMinimum Modulus Principle
DC.CreatorWeisstein, Eric W.
DC.DescriptionLet f be analytic on a domain U subset= C, and assume that f never vanishes. Then if there is a point z_0 in U such that |f(z_0)|<=|f(z)| for all z in U, then f is constant. Let U subset= C be a bounded domain, let f be a continuous function on the closed set U^_ that is analytic on U, and assume that f never vanishes on U^_. Then the minimum value of |f| on U^_ (which always exists) must occur on partialU. In other words, min_(U^_)|f|=min_(partialU)|f|.
DC.Date.Created2000-06-20
DC.Subject26
DC.RightsCopyright 1999-2026 Wolfram Research, Inc. See https://mathworld.wolfram.com/about/terms.html for a full terms of use statement.
DC.Formattext/html
DC.Identifierhttps://mathworld.wolfram.com/MinimumModulusPrinciple.html
DC.Languageen
DC.PublisherWolfram Research, Inc.
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DC.TypeText
Last-Modified2000-06-20
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