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Funkciyu f R n R displaystyle f mathbb R n rightarrow mathbb R nazivayut zamknutoyu yaksho dlya kozhnogo a R displaystyle alpha in mathbb R pidrivneva mnozhina x dom f f x a displaystyle x in mbox dom f vert f x leq alpha ce zamknuta mnozhina Totozhno yaksho nadgrafik viznachenij cherez epi f x t R n 1 x dom f f x t displaystyle mbox epi f x t in mathbb R n 1 vert x in mbox dom f f x leq t zamknutij todi funkciya f displaystyle f zamknuta Ce viznachennya pravilne dlya vsih funkcij ale najuzhivanishe dlya opuklih funkcij Vlastivosti red Yaksho f R n R displaystyle f mathbb R n rightarrow mathbb R nbsp ce neperervna funkciya i dom f displaystyle mbox dom f nbsp zamknuta todi f displaystyle f nbsp zamknuta Yaksho f R n R displaystyle f mathbb R n rightarrow mathbb R nbsp ce neperervna funkciya i dom f displaystyle mbox dom f nbsp vidkrita todi f displaystyle f nbsp zakrita todi j lishe todi koli vona zbigayetsya do displaystyle infty nbsp uzdovzh kozhnoyi poslidovnosti yaka zbigayetsya do mezhovoyi tochki dom f displaystyle mbox dom f nbsp 1 Primitki red Boyd Stephen Vandenberghe Lieven 2004 Convex optimization New York Cambridge s 639 640 ISBN 978 0521833783 nbsp Ce nezavershena stattya z matematichnogo analizu Vi mozhete dopomogti proyektu vipravivshi abo dopisavshi yiyi Otrimano z https uk wikipedia org w index php title Zamknuta opukla funkciya amp oldid 37550754